What causes most flight delays?
From August 2025 to July 2026, 39.7% of all minutes of delay came from a late-arriving aircraft: a plane that left its last airport late. The airline itself (crew, maintenance, cleaning, fueling) caused 33.3%, the air traffic system 20.7% and severe weather 6.1%. Weather also hides in the other causes: BTS counts ordinary weather that slows traffic under the air traffic system.
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Source and date
- Data as of
- Published
The data
| Cause of delay | % of all minutes of delay |
|---|---|
| Late-arriving aircraft | 39.7 |
| The airline (crew, maintenance, cleaning, fueling) | 33.3 |
| Air traffic system (congestion, airport, ordinary weather) | 20.7 |
| Severe weather | 6.1 |
| Security | 0.1 |