Heathrow Airport has apologised to passengers caught up in recent travel chaos but warned that more flights could be cancelled this summer.
Last month, airlines were told to make sure their timetables were "deliverable" after the industry struggled to cope with soaring demand.
Heathrow boss John Holland-Kaye said the airport would review the changes submitted by airlines.
But he added that Heathrow would ask for "further action if necessary".
Thousands of passengers have been affected by disruption at UK airports and flight cancellations in recent months as the industry struggles to recruit staff after axing jobs during Covid lockdowns.