Four U.S. carriers—Delta Air Lines, Alaska Airlines, Southwest Airlines and American Airlines, in that order—made the list of the 10 most punctual "mega airlines" in the world, according to OAG's 2019 Punctuality League report.
OAG labels a flight as on time if it arrives or departs within 15 minutes of its scheduled arrival or departure time. Cancellations are included within OTP's calculations and are counted as late flights. An airline is included in the report if it is ranked among the largest 250 airlines globally by annual available seat kilometers and if OAG has flight status data for at least 80 percent of the carrier's scheduled flights. "Mega airlines" are those with the most scheduled flights in 2019.