After easyJet cancelled hundreds of flights in recent days, its chief executive laid some of the blame on the Department for Transport.
easyJet boss Johan Lundgren said increasing cancellations are due to delays in processing security checks for new airline staff.
Travellers have faced cancellations this week mainly on routes serving London's Gatwick Airport.
Lundgren said this has primarily been due to staff absences related to Covid, but also blamed setbacks from the Government vetting new hires.
He said: "There's this delay of the clearance from the DfT (Department for Transport) for people to get their IDs. There’s a backlog there and we’re waiting currently for about 100 cabin crew to get their IDs.
"There's a three-week delay on that. That has had an impact. If that would have been on time, we would have seen less cancellations."
This demonstrates that the rise in coronavirus infections has "impacted basically the whole of the UK", Lundgren said.
He went on: "I understand the DfT and the ministers are doing what they can to accelerate and speed this up – which we find very constructive – but it definitely has had an impact."
The chief executive insisted "we don't have a shortage of crew" and it was "absolutely not" fair to accuse the airline of selling flights it could not fulfil.
He said: "We were having in some cases up to 20 percent of absence, and you wouldn't expect any airline at any point in time to be able to cover that.
"That is unfortunate for people who have been affected but I would like to reiterate that those cancellations were made pre-emptively.
"People got notice on that in the beginning of last week. The majority of them had the opportunity to rebook to flights that we have on the same day, however unfortunate that is.
"We're carrying up to 260,000 customers per day, so I think it's important to put that into context."
easyJet cancelled at least 23 flights to or from Gatwick on Tuesday amid Easter holidays, affecting routes between the airport and locations such as Berlin, Milan, Valencia and Venice.
The airline said cancellations are being made "in advance to give customers the ability to rebook on to alternative flights".
Lundgren said it is "too early to tell" how long the flight disruption will continue.
He told reporters: "You would expect however, that the spike that we're seeing in Covid infections that really exists here in the UK and also in (other) parts of the network, is going to come down, but this is something that we don't see yet."
easyJet said more bookings for summer flights were made during the past six weeks than in the same period in 2019.
The airline expects to operate "near" pre-pandemic levels of flying this summer. It operated at 80 per cent of 2019 capacity in the first three months of this year.
Lundgren said he is "not worried" about whether the airline will be able to ramp up its services this summer.
The number of flights currently being cancelled are a "relatively small proportion" of its total operations, with 94 percent of its planned schedule running in the last seven days, he added.
Don't miss the latest news from around Scotland and beyond - Sign up to our daily newsletter here .
