Delta Air Lines posted the best on-time arrival rate of any major U.S. carrier in June 2026, while Southwest Airlines, once known as one of the industry’s steadiest performers, finished dead last, according to new federal data from the Department of Transportation’s August 2026 Air Travel Consumer Report.
Key Points
- Delta led June with 80.8% of flights arriving on time, ahead of Alaska Airlines at 79.4% and United at 73.9%, per the Bureau of Transportation Statistics.
- Southwest’s on-time rate fell to 65.3% in June, trailing even budget carriers Frontier (69.7%) and Allegiant (68.2%).
- American Airlines had the worst cancellation rate in June at 3.4%, while Allegiant canceled just 0.5% of flights and Southwest 0.6%.
- Looking at the full first half of 2026, Alaska Airlines holds the top spot for on-time arrivals at 80.5%, narrowly ahead of Delta at 79.3% and United at 77.6%.
The June numbers are a reminder that monthly rankings can swing hard even for carriers with strong reputations. Southwest built its brand for decades on operational reliability, but its June on-time rate landed 15 percentage points behind Delta’s, even as its cancellation rate stayed near the top of the field. That split matters for travelers: an airline can rarely cancel your flight and still run late often enough to wreck a connection.
Zoom out to the year-to-date figures and a different leaderboard appears. Allegiant, which finished mid-pack on June on-time performance, has the best cancellation record of any airline through the first half of 2026 at 0.90%, with Southwest close behind at 1.05%. Alaska Airlines is the standout across both windows, finishing at or near the top of both the June snapshot and the six-month average, a consistency none of the larger network carriers matched.
The data comes from DOT’s monthly Air Travel Consumer Report, which compiles on-time arrival and cancellation figures reported directly by airlines under federal reporting requirements. Airlines had more flights to manage this June than last: carriers operated 671,781 scheduled flights nationwide in June 2026, and the first half of the year ran 3,856,905 flights total, up from 3,769,474 over the same six months in 2025, per the report. More flights in the system generally makes holding onto a strong on-time rate harder, which makes Alaska’s consistency across both the monthly and six-month windows more notable, not less.
For travelers booking fall trips, the takeaway isn’t which airline is “best” in some fixed sense, it’s that reliability rankings move fast enough month to month that last year’s most punctual carrier can slip into the bottom half within a single reporting cycle.
