Fermi question · Geography
About how many passenger journeys did airlines carry worldwide in 2025?
Make a fast, defensible estimate before you reveal the reference answer. Think in factors, not exact recall.
What is your estimate?
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Reference answer
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≈ 5 billion passenger journeys
Fermi estimates are judged by scale, so a reasonable approximation can still earn a strong score.
One way to estimate it
Estimate the share of the world that flies in a year, then allow for travelers taking more than one flight segment.
- World population≈ 8.2 billion
- People who flya minority of the world in a given year
- Repeat segmentsmany flyers take more than one trip
- Estimateorder of 5 billion passenger journeys
Keep practicing
Try another question, or return to the daily challenge to build your personal sense of scale.