Airline passengers have been hit with further disruption as more than 100 UK flights scheduled for Wednesday were cancelled.
British Airways axed at least 78 flights at Heathrow, while easyJet cancelled at least 30 at Gatwick.
The aviation industry is suffering from a surge in coronavirus-related staff sickness and a shortage of workers following job cuts made during the virus crisis.
To reduce the impact on passengers, most cancellations are being made at least a day in advance and on routes with multiple daily flights, so passengers can be offered alternative departures.
British Airways said many of its cancellations include flights cut as part of its decision last month to reduce its schedule until the end of May.
This was done to boost reliability due to rising Covid-19 cases.
The rate of staff absences at easyJet is around double normal levels.
Airports are also struggling from the combination of staff shortages and a spike in demand as many families head abroad for the school Easter holiday, which is the first since the UK’s coronavirus restrictions for international travellers were dropped.
The situation could worsen this weekend as airports will be used by travellers returning from trips during the first week of the break, and those departing for the second week of the school holiday.
Manchester Airport managing director Karen Smart resigned on Tuesday after weeks of disruption for passengers.
Travellers have faced long delays and chaotic scenes, with queues trailing outside terminals to reach check-in desks and hordes of people waiting to get through security and to pick up luggage.
Piles of suitcases have been left in terminals after travellers abandoned the wait to reclaim their baggage and instead left for home.
Passengers have also reported long queues at Heathrow and Birmingham airports.