How BTS defines "on time"

The Bureau of Transportation Statistics (BTS) counts a flight as on time if it operated less than 15 minutes later than the scheduled time shown in the carrier's reservation system. A flight that arrives 14 minutes late is on time; one that arrives 15 minutes late is not. The same 15-minute rule applies to departures.

Gate to gate

The times are gate times, not wheels-up and touchdown. Departure is when the aircraft leaves the gate; arrival is when it reaches the gate at the destination. Taxi time at both ends is inside the schedule, so a flight that takes off late can still arrive on time, and one that lands early can still be late if it waits for a gate.

Cancellations and diversions

In BTS's summary tables the shares of flights that were on time, delayed for each cause, cancelled and diverted add up to 100 percent of scheduled flights. This site follows that convention: the on-time share is on-time arrivals divided by all scheduled flights, so cancelled and diverted flights count as not on time. In the 12 months to July 2026, 76.0% of 7,043,858 scheduled flights arrived on time, 1.8% were cancelled and 0.3% diverted.

Some published figures divide by flights that actually operated instead, which gives a slightly higher share. When comparing this site with another source, check which denominator it uses.

Arrivals versus departures

Route and airline pages lead with arrival performance, which is what BTS reports as a carrier's on-time record. Airport pages lead with departures for flights leaving the airport and arrivals for flights landing there, since an airport's own conditions bear most on the flights it handles at the gate.

What the figure does not say

The on-time share is a count of outcomes. It does not separate a late flight by a few minutes from one delayed by hours; the average delay and the delay-minute figures on each page cover that. It says nothing about safety, and the past record of a route is not a forecast for any particular flight.

Related: the five delay-cause categories, which airlines report, methodology. Data on this site runs from 2023-08 to 2026-07.