Author: Taylor Warfield, Former Bain Manager and interviewer

Last Updated: July 13, 2026

 

An aerospace and defense case interview is a management consulting case built around an industry client like a defense prime, aircraft manufacturer, or space company, where you solve a business problem shaped by government contracts, long program cycles, and heavy regulation. This guide gives you the industry knowledge, case types, frameworks, and a full worked example you need to solve these cases and beat candidates who only memorized a framework.

 

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Key Takeaways

 

Aerospace and defense cases reward candidates who pair standard case structure with real industry knowledge about government contracts, program economics, and the handful of large primes that dominate the market.

 

• Expect profitability, growth, market entry, M&A, cost reduction, and pricing cases set inside the A&D industry

 

• Know the two core contract types: cost-plus, where the government absorbs overruns, and fixed-price, where the contractor does

 

• Track backlog and book-to-bill as the industry's main demand signals, since orders often run years ahead of revenue

 

• A few large primes such as Lockheed Martin, RTX, Boeing, Northrop Grumman, and Airbus anchor the market alongside thousands of smaller suppliers

 

• US defense demand sits near record highs, with the fiscal year 2026 defense authorization set around $900 billion

 

• Lead with a clean structure, then layer in industry specifics to separate yourself from candidates who only know generic frameworks

 

What Is an Aerospace and Defense Case Interview?

 

An aerospace and defense case interview is a consulting case set in the A&D industry, where the client is usually a defense contractor, commercial aircraft maker, or space company. You solve a business problem such as falling profits, a growth target, an acquisition, or a cost overrun, while accounting for government contracts, multi-year programs, strict regulation, and a small set of dominant players.

 

The case itself follows the same flow as any other. You ask clarifying questions, build a structure, work through the math, and deliver a recommendation.

 

What changes is the context around the numbers. A defense prime cannot simply raise prices on a fixed-price contract, and a commercial jet program may not break even for a decade. These industry-specific case interview dynamics are exactly what separates a strong answer from a generic one.

 

Why Do Consulting Firms Test Aerospace and Defense Cases?

 

Firms test A&D cases because the industry is large, strategically important, and full of problems that consultants get paid to solve. If you are interviewing for a practice that serves these clients, expect at least one case grounded in this sector.

 

There are four main reasons these cases show up.

 

• Real client demand: defense budgets and commercial backlogs are near record levels, so firms staff heavily here

 

• Complex economics: government contracts, long cycles, and regulation create problems that test real judgment, not pattern matching

 

• Industry fit: interviewers want to see whether you can reason inside an unfamiliar industry instead of forcing a memorized template

 

• Differentiation: most candidates know nothing about defense contracting, so a little industry knowledge stands out fast

 

The interviewer is not checking whether you can name fighter jets. The interviewer wants to see whether you can take a few industry facts and reason cleanly toward a recommendation.

 

How Big Is the Aerospace and Defense Industry?

 

The aerospace and defense industry is one of the largest manufacturing sectors in the world, and demand is at record highs. According to the Aerospace Industries Association's 2025 Facts and Figures report, the US A&D industry generated nearly $1 trillion in economic activity and supported 2.2 million jobs based on 2024 data.

 

That same report found the industry contributed $443 billion in economic value and remains the only US manufacturing sector with a net-positive trade balance. Roughly 54% of direct employment sits in defense and national security, with about 43% in commercial aerospace.

 

Two demand engines drive the sector. Government defense spending sets the floor, and the fiscal year 2026 National Defense Authorization Act, passed in December 2025, authorized around $900 billion for the Department of Defense. On the commercial side, PwC's 2026 global aerospace and defense report noted that the commercial aircraft order backlog crossed $1 trillion for the first time in 2025.

 

A handful of large primes dominate. These are the companies that win the biggest government and commercial programs, then push work down to thousands of suppliers.

 

Company	Primary focus	Example programs
Lockheed Martin	Defense	F-35 fighter, missile systems, space
RTX (Raytheon)	Defense and commercial	Missiles, radars, Pratt & Whitney engines
Boeing	Commercial and defense	737 and 787 jets, defense aircraft
Northrop Grumman	Defense	B-21 bomber, space and missiles
Airbus	Commercial and defense	A320 and A350 jets, helicopters

 

To put scale in perspective, Lockheed Martin alone reported $71 billion in net sales for 2024 and a record backlog of $176 billion, according to its full-year results. A backlog that size means demand is locked in years ahead of when revenue gets recognized.

 

What Industry Knowledge Do You Need for an Aerospace and Defense Case?

 

You need a short list of industry facts, not an engineering degree. Five concepts cover most of what an interviewer expects you to reason about: contract types, backlog signals, the program lifecycle, the primes-and-suppliers structure, and the commercial-versus-defense split.

 

Cost-plus versus fixed-price contracts

 

This is the single most useful concept to know. In a cost-plus contract, the government reimburses the contractor's costs plus an agreed fee, so the government carries most of the overrun risk. In a fixed-price contract, the contractor commits to one price, keeps any savings, and absorbs any overrun itself.

 

The industry has moved toward fixed-price deals, which shifts risk onto contractors and squeezes margins. The stakes are real: Lockheed Martin recognized $1.7 billion in losses on a classified fixed-price program in the fourth quarter of 2024 alone. If a case involves a margin problem on a development program, contract type is often the first place to look.

 

Backlog and book-to-bill

 

Backlog is the value of orders a company has won but not yet delivered. Book-to-bill is the ratio of new orders to revenue in a period, and a number above 1.0 means the backlog is growing.

 

These two metrics are the industry's clearest demand signals. When a case asks whether future revenue looks healthy, backlog and book-to-bill tell you more than a single year of sales.

 

The program lifecycle

 

A&D programs run through three broad phases: development, production, and sustainment. Development is expensive and often loses money, production is where volume and margins ramp, and sustainment covers decades of maintenance, repair, and upgrades.

 

This matters because profitability depends heavily on which phase a program is in. A jet that loses money in development can earn steady profit for thirty years of sustainment.

 

Primes versus suppliers

 

Primes are the large contractors that win the top-level government or airline contract. They sit above a deep base of suppliers that build engines, avionics, structures, and components.

 

Where your client sits in this chain changes its options. A prime negotiates directly with the government, while a tier-two supplier depends on the primes above it and a much smaller customer base.

 

Commercial versus defense

 

Commercial aerospace sells to airlines and follows air travel demand, fuel prices, and economic cycles. Defense sells to governments and follows budgets, geopolitics, and procurement timelines.

 

The same company can play in both, and the two sides behave very differently. A defense order is more predictable, while a commercial order swings with the economy.

 

Keep this glossary handy as a quick reference.

 

Term	What it means in a case
Prime	The lead contractor that holds the top-level government or airline contract
Cost-plus	Government pays costs plus a fee, so the government carries overrun risk
Fixed-price	Contractor commits to one price and absorbs any overrun itself
Backlog	Value of orders won but not yet delivered, a forward demand signal
Book-to-bill	New orders divided by revenue, where above 1.0 means growth
Sustainment	Ongoing maintenance, repair, and upgrade work over a program's life

 

What Types of Aerospace and Defense Cases Should You Expect?

 

Most A&D cases fall into six familiar case types, just dressed in industry clothing. The skill is recognizing the underlying type, then adapting your structure to the sector.

 

Case type	Typical A&D version
Profitability	A defense supplier sees margins fall on a fixed-price program
Growth strategy	A commercial jet maker wants to grow revenue over five years
Market entry	A prime weighs entering the commercial drone or space market
Mergers and acquisitions	A contractor evaluates buying a smaller supplier for capability
Cost reduction	An aircraft maker must cut unit cost to win a fixed-price bid
Pricing	A supplier prices a new component or aftermarket service

 

Because defense work runs through government programs, many of these overlap with a public sector case interview, where the buyer is a government rather than a private firm. Recognizing the case type early lets you pull the right structure quickly.

 

How Do You Structure an Aerospace and Defense Case?

 

Structure an A&D case the same way you structure any case: build a clear, logical breakdown of the problem, then add the industry factors that matter. You do not need a special template, and you should never invent one on the spot.

 

Start from the standard case interview frameworks you already know, then bend each branch to fit the sector. Here is how the most common types adapt.

 

Profitability

 

Break profit into revenue and costs, as you would in any profitability case interview. On the revenue side, separate programs by contract type and lifecycle phase, since a fixed-price development program behaves nothing like a mature sustainment one.

 

On the cost side, look hard at program overruns, supply chain disruptions, and labor. In this industry, a single troubled fixed-price program can sink an otherwise healthy segment.

 

Growth and market entry

 

For a growth strategy case, split growth into existing programs, new programs, and adjacent markets like space or unmanned systems. Weigh how much of each opportunity is commercial versus government, because the risk profiles differ sharply.

 

For market entry, size the opportunity, assess barriers like regulation and clearances, and check whether the client's capabilities and customer relationships transfer. Defense buyers value track record, so a credible entry usually leans on an existing program or an acquisition.

 

Mergers, cost, and pricing

 

Treat merger and acquisition cases as a question of capability, backlog, and synergy, and confirm whether regulators would clear a deal between large primes. For cost reduction, focus on the levers that win fixed-price bids: design simplification, supplier negotiation, and production efficiency.

 

Pricing cases hinge on whether the contract is cost-plus or fixed-price, since that determines how much pricing freedom the client has. Aftermarket and sustainment pricing often carries the best margins, so flag it.

 

If you want to sharpen the structuring skills that carry across every one of these, my case interview course walks you through proven methods in as little as 7 days.

 

Sample Aerospace and Defense Case Interview

 

Here is a full worked example so you can see how industry knowledge shapes a real answer. Read the prompt, then try structuring it before reading the walk-through.

 

Prompt: Your client is a defense supplier that builds avionics systems. Over the past two years, its operating margin on its largest program dropped from 12% to 4%, even though revenue stayed flat. The CEO wants to know what is driving the decline and what to do about it.

 

Step 1: Clarify. A strong candidate opens with a few sharp clarifying questions before structuring. What type of contract is this program, cost-plus or fixed-price, and which lifecycle phase is it in?

 

Let's say the interviewer tells you it is a fixed-price program that recently moved from development into early production. That single fact reframes the whole case.

 

Step 2: Structure. Since revenue is flat, the margin drop must come from rising costs. Break costs into material and supply chain, labor and engineering, and program overruns or rework.

 

• Material and supply chain: are component prices rising or are suppliers missing deliveries

 

• Labor and engineering: is the client adding engineers to fix design issues found in development

 

• Overruns and rework: on a fixed-price deal, every overrun comes straight out of margin

 

Step 3: Analyze the math. Assume the program generates $500 million in annual revenue. At a 12% margin, operating profit was $60 million, and at 4% it is now $20 million, a $40 million drop.

 

The interviewer shares that material costs rose by $15 million and rework added $25 million in extra labor. That accounts for the full $40 million gap, and because the contract is fixed-price, none of it can be passed to the customer.

 

Step 4: Recommend. The margin fell because a fixed-price program hit cost overruns the client cannot bill back. The client should stabilize the design to stop rework, renegotiate or dual-source key suppliers, and price future bids with realistic development risk built in.

 

Notice that the recommendation only works because you used industry knowledge. A generic cost answer would miss why the contract type makes this margin loss permanent.

 

How Do You Do the Math in an Aerospace and Defense Case?

 

The math in A&D cases is standard business arithmetic, so clean execution matters more than fancy techniques. The same case interview math you practice for any case applies here, with a few industry-flavored calculations.

 

Three calculations come up often.

 

1. Book-to-bill: divide new orders by revenue, so $13 billion in orders against $10 billion in revenue gives a ratio of 1.3 and a growing backlog
   
   
2. Program margin: multiply revenue by margin to find profit, then test how a cost overrun changes it on a fixed-price deal
   
   
3. Market sizing: estimate a segment like military drones by units, price per unit, and replacement cycle

 

For a quick market sizing example, suppose a country operates 1,000 large military drones, each costs $10 million, and they get replaced every 10 years. That implies roughly $1 billion in annual replacement demand before you add new fleet growth.

 

Always narrate your assumptions out loud and use round numbers. The interviewer cares more about logical setup than decimal precision.

 

Tips for Your Aerospace and Defense Case Interview

 

These tips come from coaching hundreds of candidates through industry-specific cases. Apply them and you will sound like someone who already understands the sector.

 

Tip #1: Identify the contract type early

 

Whether a program is cost-plus or fixed-price changes almost every downstream conclusion. Ask about it in your clarifying questions and let the answer shape your structure.

 

Tip #2: Separate commercial from defense

 

The two sides follow completely different demand drivers and risk profiles. Splitting them early shows the interviewer you understand how the industry actually works.

 

Tip #3: Think in program lifecycles

 

A program that loses money today may be highly profitable in sustainment years later. Tie any profitability conclusion to where the program sits in its lifecycle.

 

Tip #4: Use backlog as your crystal ball

 

When a case asks about future health, reach for backlog and book-to-bill instead of a single year of revenue. It signals that you know how this industry forecasts demand.

 

Tip #5: Respect regulation and clearances as real barriers

 

Export controls, security clearances, and procurement rules slow entry and protect incumbents. Treat them as genuine barriers in a market entry case, not throwaway risks.

 

Tip #6: Ground your numbers in reality

 

Before your interview, skim a recent earnings release from a major prime to anchor your sense of scale. Knowing that a top prime books tens of billions in revenue keeps your estimates credible.

 

Tip #7: Close with a structured recommendation

 

Finish with a crisp case interview recommendation that states your answer, your reasons, the risks, and the next steps. A clear close lands far better than trailing off after the math.

 

If you want feedback on how you handle these cases live, my interview coaching pairs you one-on-one with a former Bain interviewer to pressure-test your performance.

 

Which Consulting Firms Hire for Aerospace and Defense Work?

 

Many top firms run dedicated aerospace and defense or public sector practices. Knowing which firm leans commercial and which leans government helps you predict the kind of case you will get.

 

• Strategy firms: McKinsey, BCG, and Bain advise both commercial aircraft makers and defense primes on strategy and operations

 

• Government-focused firms: Booz Allen Hamilton and Deloitte run large public sector practices serving defense and national security clients

 

• Operations and turnaround firms: several advisory firms specialize in cost, supply chain, and program recovery for the sector

 

If your target leans heavily toward government work, it is worth studying the public sector consulting firms that dominate defense contracting, since their cases skew toward procurement and program economics. Tailoring your prep to the firm's client base is the quickest way to walk in ready.

 

Cracking an aerospace and defense case interview comes down to one move: lead with a clean structure, then layer in the handful of industry facts that change the answer. Master the contract types, program lifecycle, and backlog signals, and you will outperform the many candidates who treat every case the same.

 

Frequently Asked Questions

 

Is an aerospace and defense case interview different from a normal case interview?

 

The structure is the same, but the context changes how you reason. You still build a clear framework and run the math, yet you apply industry facts like government contracts, multi-year program cycles, and the small set of dominant primes. Candidates who add that industry layer stand out from those who only recite a generic framework.

 

What industry knowledge do I need for a defense case interview?

 

Know the two main contract types, cost-plus and fixed-price, and who carries the overrun risk in each. Understand backlog and book-to-bill as demand signals, the development to production to sustainment program lifecycle, and the split between commercial aerospace and government defense work. You do not need an engineering degree to reason about these clearly.

 

What is the difference between cost-plus and fixed-price contracts?

 

In a cost-plus contract, the government reimburses the contractor's costs plus an agreed fee, so the government absorbs most overrun risk. In a fixed-price contract, the contractor agrees to one price and keeps any savings but eats any overruns. The industry has shifted toward fixed-price deals, which puts more pressure on contractor margins.

 

Which consulting firms work in aerospace and defense?

 

Strategy firms like McKinsey, BCG, and Bain advise commercial and defense clients, while government-focused firms such as Booz Allen Hamilton and Deloitte run large public sector practices. Operations and turnaround firms also serve aircraft makers and suppliers. Many of these firms test A&D cases when they recruit for relevant practice areas.

 

How do I prepare for an aerospace and defense case interview?

 

Master standard case skills first, then study a short list of industry facts: contract types, program economics, key players, and current demand drivers. Practice two or three A&D cases out loud with a partner, focusing on building structure and doing clean math. Read recent earnings releases from a major prime to ground your numbers in reality.

 

Do I need a security clearance or technical background to work in defense consulting?

 

For the interview, no. Firms test business judgment, not classified knowledge or engineering depth. Some defense projects later require a security clearance, which the firm or client typically sponsors after you join, so it is not something you need before your case interview.

 

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