Google·Product Manager·Onsite - Product Sense / Strategy·Senior

Senior

May 2026

Summary

Google PM interview with a classic estimation question. Pretty standard product sense round but this one had enough moving parts to trip you up if you weren't careful about your assumptions.

Questions Asked (1)

How many drones would be needed to replace all FedEx package deliveries across the US?

Product Analytics & MetricsAdaptability & AmbiguityProduct Strategy

Author's notes

I started with total US packages per day, which I ballparked around 15 million across all carriers, then tried to figure out FedEx's rough share.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the scope and assumptions, then break the problem into a demand side (number of packages per day) and a supply side (drone capacity per day). Use a top-down estimation approach, state your assumptions clearly, and calculate the number of drones needed, while acknowledging operational constraints and trade-offs.

Pro tip: Don't get lost in precise numbers; focus on the logic and structure. Mention that this is a Fermi problem and that the goal is to demonstrate structured thinking, not to get the exact answer. Also, consider the product strategy implications: would drones replace all deliveries or only a subset?

1. Clarify scope and assumptions

Ask clarifying questions to define the problem: Are we replacing all FedEx deliveries, including express and ground? What is the time frame? Are we considering only the US? State assumptions about drone capabilities, regulations, and infrastructure.

2. Estimate total daily package volume

Calculate the number of packages FedEx delivers per day in the US. Use known data: FedEx handles ~6 million packages per day in the US (or estimate from revenue, population, etc.). Break down by residential vs. commercial if needed.

3. Estimate drone delivery capacity

Determine how many packages a single drone can deliver per day. Consider factors: flight time, payload capacity, recharge time, distance between stops, and operational hours. For example, if a drone can carry 1 package per trip, takes 30 minutes per trip including recharge, and operates 10 hours/day, it can do 20 deliveries/day.

4. Calculate number of drones needed

Divide total daily package volume by daily capacity per drone. For example, 6 million packages / 20 deliveries per drone = 300,000 drones. Adjust for utilization, maintenance, and redundancy.

5. Sanity check and discuss limitations

Validate the number against practical constraints: airspace management, regulations, weather, and cost. Discuss whether this is feasible and what trade-offs exist. Consider if a hybrid model (drones + trucks) is more realistic.

Key Points to Mention

Clarify the scope: all FedEx deliveries vs. a subset, US only, time frame.
Use a top-down estimation: total packages per day / deliveries per drone per day.
State assumptions explicitly: drone payload, speed, range, recharge time, operating hours.
Consider operational constraints: regulations, airspace, weather, infrastructure, cost.
Acknowledge that this is a Fermi problem; focus on logic, not exact numbers.
Discuss product strategy: is full replacement realistic? What are alternatives?

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.