Estimation question

Estimate the market size of an online flight insurance business in the US.

Practice this question out loud. An AI interviewer asks it, follows up like a real interviewer would, and scores your answer. Type or speak.

What this question tests

Market sizing with a TAM-SAM-SOM approach: can you narrow a broad category (insurance) into a specific, defensible addressable market estimate.

Define the market: US domestic flight passengers who could purchase optional flight-specific insurance (delay/cancellation coverage), not broader travel insurance.
Estimate total US domestic flight passengers per year (state a plausible figure as assumption) as the top of the funnel.
Estimate attach rate: the percentage of passengers who would actually opt to buy standalone flight insurance, which is typically a small minority given many already have some protection via credit cards.
Estimate average price per policy based on comparable existing travel insurance products.
Multiply passengers x attach rate x price to get an annual market size estimate, clearly separating TAM (all passengers), SAM (addressable via this channel), and SOM (realistic near-term capture).
State the biggest uncertainty: the attach rate assumption, since it's the hardest number to estimate without real data.

Structures the estimate as TAM/SAM/SOM explicitly, showing a disciplined market-sizing framework rather than one flat number.
Uses a low, realistic attach rate assumption, correctly recognizing most travelers don't buy standalone insurance products.
Ties the price assumption to comparable existing insurance products instead of guessing arbitrarily.
Flags attach rate as the single biggest source of uncertainty, showing awareness of which assumption matters most.

Sizing the whole US flying population as the addressable market without discounting for realistic attach rate.
Not separating TAM from a realistic near-term SOM, presenting an inflated market size as the answer.

How would you validate the attach rate assumption before committing to build this?
How would this market size change if bundled automatically into ticket purchase versus sold as an opt-in add-on?