Which airlines report

A flight is counted as on time if it arrived less than 15 minutes after its scheduled time. Only carriers with at least 0.5 percent of domestic scheduled passenger revenue report. The rule is 14 CFR Part 234. The threshold was 1 percent until 2018, when it fell to 0.5 percent and several more carriers began reporting.

Carriers on this site

14 carriers reported domestic on-time data in the 12 months to July 2026:

Code	Reporting carrier	Flights	On time
WN	Southwest Airlines	1,389,951	75.5%
DL	Delta Air Lines	1,038,644	79.9%
AA	American Airlines	987,645	72.7%
OO	SkyWest Airlines, a regional carrier that operates flights sold by Alaska, American, Delta and United	854,130	77.4%
UA	United Airlines	825,693	78.2%
YX	Republic Airline, a regional carrier that operates flights sold by American, Delta and United	363,168	75.3%
MQ	Envoy Air, a regional carrier that operates American Eagle flights	317,726	78.9%
AS	Alaska Airlines	301,435	78.5%
OH	PSA Airlines, a regional carrier that operates American Eagle flights	242,215	70.7%
B6	JetBlue Airways	237,090	69.9%
F9	Frontier Airlines	209,405	71.6%
G4	Allegiant Air	126,499	73.3%
NK	Spirit Airlines	117,136	69.8%
HA	Hawaiian Airlines	33,121	81.2%

Regional carriers

Many flights sold as American Eagle, Delta Connection, United Express or Alaska are flown by regional carriers under contract. BTS records the carrier that operated the flight, so those flights appear under the regional carrier's own code, for example SkyWest (OO), Republic (YX), Envoy (MQ), PSA (OH) or Endeavor (9E), and not under the brand on the ticket. A large airline's figure on this site therefore covers only the flights it operated itself.

What the files leave out

Carriers below the revenue threshold, including most small regional and commuter airlines.
International flights, including those of the reporting carriers. Only flights between points within the United States and its territories are covered.
Charter, cargo-only and foreign airlines.
Flights in a month before a carrier started reporting or after it stopped, merged or ceased operations.

Airport totals are therefore smaller than the airport's real traffic, and a route with a non-reporting carrier will show fewer flights than actually operated.