Punctuality improved at all 10 UK airports monitored by the CAA in the first quarter of this year, with Heathrow showing the largest increase.
The average delay on inbound and outbound flights from Heathrow halved in the first quarter of 2009, compared with the same period last year, according to figures from the Civil Aviation Authority (CAA).
The average delay on scheduled flights fell from 24 minutes to 12 minutes, while London City airport also halved its average delay to nine minutes.
The number of scheduled flights that arrived on time or up to 15 minutes late, increased by 11%, to 81%, compared with the same period in 2008.
Over the same period, the number of flights arriving and departing at these airports fell 9%, and passengers numbers decreased by 11%.
In terms of destinations, flights to Istanbul from the UK recorded the worst performance, with just 58% arriving on time, and flights to Toronto had the highest average delay of 22 minutes.
Flights to Rotterdam had the highest number of flights arriving on time, and those to Luxembourg the shortest average delay of five minutes.
The study did not include flights that were cancelled.