BA spokesman Jamie Bowden said: "Most of our flights from other UK airports are going pretty much according to plan at the moment."
There were further delays on Sunday, but a British Airports Authority (BAA) spokeswoman at London Heathrow said the situation had improved markedly.
There are still some delays at Stansted and Gatwick, and early on Monday two planes were cancelled at Aberdeen airport.
Thousands of travellers were stranded over the weekend, with some forced to sleep overnight at airports.
Sir Bobby Charlton - who had been due to fly to Belgium to watch the England-Germany match - and Tory leader William Hague were among those who had to cancel their travel plans.
The delays continued even though the problem with the National Air Traffic Services computer, which handles all aircraft entering UK airspace, was fixed by Saturday afternoon.
"Not as bad"
"It has not been as bad as Saturday. We had 317 cancellations out of 1,250 flights on Saturday but on Sunday we only had about 130 cancellations," said the BAA spokeswoman.
A spokeswoman for Gatwick airport said about two-thirds of flights had been affected on Sunday, with delays averaging three to four hours.
BA spokesman Jamie Bowden said: "Most of our flights from other UK airports are going pretty much according to plan at the moment."
NATS has promised a "thorough investigation" into the computer breakdown, the second time the system has failed in a week.
The problem meant that flight course information, normally passed electronically, had to be retrieved by hand.
A NATS spokesman said the problem was not "safety critical".