British Airways has canceled a further 1,500 flights, mostly for July in the hope of avoiding a repeat of the airport disruption witnessed earlier this year.
The wave of cancellations made over the past weeks will affect tens of thousands who hope to fly this summer from Heathrow and Gatwick.
British Airways had already removed 10% of scheduled flights between April and October but said that "regrettably" more cancellations were needed.
"We took pre-emptive action earlier this year to reduce our summer schedule to provide customers with as much notice as possible about any changes to their travel plans,” a spokesperson from the airline, which is The UK's largest, said.
"As the entire aviation industry continues to face into the most challenging period in its history, regrettably it has become necessary to make some further reductions,” he added
The air carrier mentioned that it was in touch with customers to "apologize and offer to rebook them or issue a full refund".
British Airways is expected to announce more cancellations over the summer before the deadline.
The cancellations come as hundreds of British Airways check-in staff at Heathrow are deciding which strike dates could further affect the peak travel period for the summer school holiday.
Many jobs in the aviation industry were lost during the course of the Coronavirus pandemic and recruiting enough staff in time to deal with the surge in demand for travel has proven difficult for airlines and airports.