How Many Airports Are in the US and the World? Acing Your FAANG Interview with Structured Thinking

This guide equips aspiring product managers with the tools to tackle a common interview question: “How many airports are in the US and in the world?” We’ll explore the Fermi Problem framework, a structured approach to estimate complex unknowns.

Applying the Fermi Problem Framework

1. Define the Problem Boundaries:

   What constitutes an airport? We’ll consider both commercial and general aviation airports.

2. Establish Key Segments:

   Break down the problem into segments like commercial airports, private airstrips, and military airbases.

3. Top-Down Estimation:

   Use known data points to estimate unknown values. For example, the number of large metropolitan areas can help approximate commercial airports.

4. Bottom-Up Estimation:

   Analyze a small, familiar area and extrapolate those findings. You might estimate the number of airports in a known state and apply that ratio to the rest of the country.

5. Fact Check and Validate:

   Compare your estimates with readily available statistics to ensure they’re reasonable.

Example:

Let’s say there are 20 major cities in a state, each having at least one major airport. We can approximate 50 states; thus, estimate around 1,000 commercial airports in the US. Using various sources, we could verify and adjust this rough estimate.

Next, we’ll extrapolate to the global scale. If the US has about 1,000 commercial airports, and it represents roughly a twentieth of the world’s population, we could assume the existence of up to 20,000 airports worldwide when considering all types. However, this may not be proportional to population.

Always contextualize your assumptions and be prepared to defend them with logic. For example, if you assume denser population centers have more airports, support that with examples or known trends.

Communicating Effectively During the Interview

• Clarity: Clearly articulate each step of your estimation. Use simple language and avoid industry jargon unless you’re certain the interviewer understands it.
• Brevity: While detail is important, be succinct. Don’t let your answer drag on; keep to the essential points.
• Confidence: Speak with conviction. If you’ve made logical assumptions, stand by them unless presented with concrete data to reconsider.
• Responsive: Actively listen to the interviewer and adapt your answer if they provide new information.

Conclusion

Applying frameworks like the Fermi Problem during an interview can help structure your thoughts and communicate your analytical prowess. Though our estimation of airports may not be precise, the method demonstrates clarity of thought and problem-solving skills. As practice makes perfect, regularly challenge yourself with similar questions and refine your approach using today’s strategies and tips. Good luck on your journey to becoming a successful product manager!