The punctuality of scheduled and charter airlines deteriorated in the final quarter of last year.
Civil Aviation Authority figures show on-time performance, which is defined as no more than 15 minutes late, fell from 73% to 68% year on year across UK airports.
Stansted recorded the worst charter performance, with 65% of services on time – 10% lower than the previous year.
Average delays on charter flights rose from 23 to 29 minutes. However, much of the deterioration was due to severe fog in the days leading up to Christmas.
Scheduled services to New York JFK and Mumbai recorded the highest average delays.