Frequently Asked Questions
Where does PlainFlights' data come from?
All data comes from the Bureau of Transportation Statistics (BTS) On-Time Performance database, part of the U.S. Department of Transportation. The BTS collects monthly flight-level data from all U.S. airlines above the DOT reporting threshold.
What counts as an 'on-time' flight?
Per DOT standards, a flight is on-time if it departs or arrives less than 15 minutes after its scheduled time. Any delay of 15 minutes or more is counted as late. This is the standard BTS definition used across all PlainFlights statistics.
What is a 'NAS delay' and how is it different from a weather delay?
A NAS (National Aviation System) delay is caused by factors within the air traffic control system, including ATC congestion, airport ground stops, runway conditions, or system-wide capacity issues. A weather delay specifically results from meteorological conditions that directly impact flight safety. Weather delays tend to be shorter in duration than NAS delays at busy hub airports.
Does PlainFlights cover international flights?
No. PlainFlights covers U.S. domestic flight segments only. International routes departing from or arriving in the U.S. are not included in the BTS On-Time Performance dataset that PlainFlights uses.
Why is my regional airline not listed?
The BTS reporting requirement applies to airlines transporting 10 or more passengers on at least one route. Small regional carriers that operate below this threshold are not required to report and will not appear in PlainFlights data.
How far back does PlainFlights data go?
PlainFlights covers 38.3 million domestic flight segments from 2020 through 2025. This five-year window allows comparison of pre-pandemic (early 2020), pandemic recovery, and post-recovery performance across airports, airlines, and routes.
Is PlainFlights affiliated with BTS or any airline?
No. PlainFlights is an independent data portal built by PlainFlights. We present publicly available BTS data in a searchable format but are not affiliated with the Bureau of Transportation Statistics, Department of Transportation, or any airline.