British Airways canceled some flights Thursday, marking the fourth consecutive day of disrupted services due to staff shortages and technical difficulties.
The airline scrapped a scheduled flight from Baltimore, Md., to Heathrow Airport and a round-trip flight from Heathrow to Amsterdam, citing technical problems.
Round-trip flights from the airport to Oslo and Zurich were canceled because of staff shortages.
The airline has canceled almost 90 European and U.S. flights over the past three days, stranding thousands of travelers at the height of the busy summer vacation period.
British Airways spokesman Tony Cane said he did not expect any more cancellations on Thursday but warned the airline could merge some services over the next few days because of staff shortages.
The airline has declined to predict how it will operate over the upcoming public holiday weekend, traditionally one of the busiest times of the year.
Chief executive Rod Eddington and 11 other directors have pledged to work at Heathrow over the weekend to help run things smoothly.
The airline last week headed off a strike planned for the weekend by offering its baggage handlers and check-in staff more pay. Workers have complained they are underpaid and overworked, particularly during the summer vacation periods at Heathrow.