Airline on-time performance (OTP) in May fell 5.3 percentage points month over month to 74.4%, according to the latest report from Cirium, an aviation analytics provider. All 10 carriers in the report saw declines against April, and no North American airline was in the global Top 10 for OTP.

Delta Air Lines enjoyed the best performance in North America with an OTP of 81%, followed by Alaska Airlines at 79% and WestJet at 77.6%. The largest decline was for American Airlines, down 10.2 percentages points to 69.6%, giving it the second-worst record. Frontier Airlines was last at 65.5%.

Air Canada had the smallest decline at 1.2 percentage points below April (74%) and Alaska was next, down 1.4 percentage points to 79%.

North American carriers canceled 11,491 flights in May, against 6,217 in April. Completion factors for most airlines was similar to April’s performance, with Alaska and JetBlue both at 99.61% and Delta at 99.6%.