In January, UK-based air travel intelligence company OAG published the on-time performance of airlines and airports, based on data from 2018. The league is based on 58 million flight records using full-year data from 2018 to create a ranking of the best on-time performance (OTP) for the world’s largest airlines and airports.

Airports were split into five categories, starting from small, medium, large, major and mega, and they had to have a minimum of 2.5 million departing seats to be included in the report.