British Airways said it had cancelled 126 flights due to have flown to and from London Heathrow on Sunday because of heavy snowfall and persistent problems with the airport's new terminal.
A BA spokeswoman said 114 flights had been cancelled because of snow and 12 owing to computer glitches at the recently opened Terminal 5.
Heavy snowfall, which fell across many parts of Britain overnight and early today, also forced BA to cancel 32 flights arriving and departing London Gatwick.
"Air traffic control has reduced the number of aircraft that can take off and land per hour," the BA spokeswoman said in a statement.
A spokeswoman for BAA, the operator of Heathrow, said both of the airport's runways were briefly shut today to de-ice tarmac.
British Airways meanwhile blamed BAA for the cancellation of 12 flights owing to technical glitches.
"As a result of the continuing BAA baggage system failure in Terminal 5 we have had to cancel six shorthaul return flights (six in and six out) on Sunday," the airline said in a statement.
"We are urging BAA to resolve these issues as soon as possible."
British Airways had hoped to operate a full schedule yesterday for the first time since the new terminal opened on March 27. Instead, it had to cancel 24 short-haul flights at the start of the weekend.