Data & method
US airline delays, month by month
The records and choices behind this chart.
Dataset
US flight delays: files, columns and available downloads ↗
2020–2024 · 20,959 airport-month rows
Method
The original chart script groups route records by airline and month from 2021 onward and weights monthly delay averages by total_flights. That is an approximation: valid delay/cause denominators differ, and the compiled file lacks them. Use raw BTS records and eligible denominators for accurate multi-month means. The chart reads the separate route table; the free airport CSV does not reproduce it.
Check the scope
These notes describe the analysis method and current compiled export. A historical chart may use an earlier snapshot; use the file checksum and coverage notes when reproducing or updating it.