Delta Air Lines led North American Airlines in May with an on-time percentage (OTP) of 82.6%, according to the latest research from Cirium. Delta was followed by Alaska Airlines (82.2%), American Airlines (79.1%) , United Airlines (78%) and Southwest Airlines (77.8%). Globally, All Nippon Airlines led the way with an OTP of 92.1%. It was followed by JAL (91.1%) , LATAM Airlines (88.4%), Avianca (87.53%) and Azul (87.5%). Delta, American and United ranked sixth, seventh and eighth globally. A flight is considered on time if it arrives at the gate within 15 minutes of the scheduled arrival time. Cirium for North America reviewed carriers that are in the top 20% in terms of flight frequency, total seats and available seat kilometers.

Cirium also ranked airports with Haneda Airport (Tokyo) taking the top spot globally with an OTP of 95.3%, almost 10 points above the runner-up, Salt Lake city Airport (84.9%). Rounding out the top five were Adolfo Suarez-Madrid Barajas Airport (84.4%), Oslo Airport Gardermoen (83.4%) and El Dorado International Airport in Bogotá (82.6%)