An air traffic control fault temporarily halted services at Birmingham airport yesterday.
The technical glitch happened at 6pm and led to flights being suspended or diverted.
Services resumed later in the evening after Eurocontrol reported a failure of the electronic flight plan system.
Passengers due to board flights reported having to wait for hours and complained of long delays.
An airport spokesman said: “Following the earlier air traffic control technical fault, Birmingham airport has now resolved the issue and operations have now resumed.
“We thank passengers for their patience and apologise for any inconvenience this has caused.”