After rebounding in April, the May on-time performance for North American carriers again reversed course, dropping 5.3 percentage points month over month to 74.4 percent, according to the latest report from aviation analytics company Cirium.
Each of the 10 carriers in the report posted a decline from April, and none of the North American carriers placed among Cirium's global top 10 airlines for on-time performance.
Delta Air Lines remained in first place in North America with a May on-time performance of 81 percent, followed by Alaska Airlines at 79 percent and WestJet at 77.6 percent. It's the second month in a row that WestJet, which typically comes in the bottom half of measured carriers, landed among the top three performers.
The carrier with the largest average month-over-month decline was American Airlines, down 10.2 percentage points, which placed it as the second-lowest performing airline in North America for May. Spirit declined 9.2 percentage points, and Southwest dropped 8.2 percentage points.
The carriers with the lowest declines were Air Canada at 1.2 percentage points below its April average and Alaska, down 1.4 percentage points.
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North American carriers in May canceled 11,491 flights, not quite double the 6,217 flights canceled in April.
Completion factors for North American carriers mostly held steady, with Alaska and JetBlue each at 99.61 percent and Delta at 99.6 percent.
A flight is considered on time if the aircraft arrives at the gate within 15 minutes of its scheduled arrival time.
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