Airlines are to be financially compensated following the flight disruption caused by last week's air traffic control computer glitch.
Around 120 flights had to be cancelled and 500 were delayed by an average of 45 minutes following the computer failure at the headquarters of air traffic control company Nats at Swanwick in Hampshire.
Heathrow was the worst-hit airport, with 10,000 passengers affected. Luton and Gatwick also suffered flight disruption.
In a statement yesterday Nats said: "Nats confirms that there will be a financial consequence for the company from the delay caused by the technical problem at Swanwick on December 12 2014.
"Under the company's regulatory performance regime, customers (airlines) will receive a rebate on charges in the future. The amount is being calculated and will be notified to customers in due course."
Passengers caught up in the disruption will have to seek compensation through their airline.
British Airways said it had provided hotel accommodation to those who were disrupted last Friday. It added that passengers who were due to travel last Friday evening from Heathrow, Gatwick or London City had been offered the option to either rebook their flight for a later date or claim a full refund.
Yesterday the bosses of Nats appeared before the House of Commons Transport Committee to explain last week's problems.
Apologising to "customers, airports and the travelling public" for the computer problem, Nats chief executive Richard Deakin said his company's contingency and back-up plans worked well.
He told the committee: "Any complex system will have failures," adding that it would be "unrealistic" to expect there would be no failures.
Mr Deakin was appearing with Nats operations managing director Martin Rolfe as well as Andrew Haines, chief executive of the Civil Aviation Authority, which has already announced that an independent inquiry will be held into the failure.
The committee had already taken evidence this week from Transport Secretary Patrick McLoughlin, who described the flight delays as "unacceptable".
Questioned about the independence of the inquiry, Mr Haines said it would be "highly independent".
Mr Rolfe told MPs that the piece of equipment that failed last week dated from the mid-1990s and had dealt with 20 million flights and had been upgraded continually.
Asked if he agreed with Mr McLoughlin that the failure last week was "unacceptable", Mr Deakin said: "For the passengers who got caught up in all this, yes, it was unacceptable, and by implication it was unacceptable for us as well.
"We are not proud of what happened. We are proud of how we responded."
It was put to Mr Deakin that he sounded "very, very complacent".
He replied: "Not at all."
Mr Deakin confirmed that, including a £272,000 bonus, he received a £1.05 million pay package for the 12 months ending last March.
He also confirmed that the bonus was cut by 12% due to the flight disruption caused by another Swanwick problem last December.
Asked if he expected to have this year's bonus cut, Mr Deakin said that would be up to the Nats remuneration committee but he added that any bonus would be linked to performance.
Asked about future performance, Mr Deakin said: "I can guarantee that this particular problem will not happen again but I cannot honestly sit here and say we will never have a computer glitch again."
Mr Haines said he hoped that the full report by the inquiry team would be published by the end of March.
Mr Rolfe disagreed with a suggestion that Nats' systems were "fundamentally flawed". Incidents such as last Friday's and the one last December were "very rare and very regrettable", he added.
Mr Deakin said that latest figures showed 99.7% of flights using UK air space face no delays. Of the 0.3% that do, the average delay is 26 minutes.
Following last week's disruption Business Secretary Vince Cable had questioned Nats' investment levels. Mr Deakin said there was no question of putting profit before investment and that investment levels were between 1.4 and 1.9 times higher than before the company was privatised.
He denied any suggestion that Nats' systems were "ancient or antiquated". He said: "Just because technology is 'old', it does not necessarily mean that it is not fit for purpose."