The airline, which also reported flying nearly 140 million passengers last year, said the permit means it can "operate UK domestic and UK to non-EU routes in a post-Brexit environment, if necessary".
British Prime Minister Theresa May and the 27 EU leaders reached a draft withdrawal agreement in November that is meant to pave the way for Britain's smooth exit from the bloc on March 29.
But the deal faces strong resistance in the British parliament, which is set to vote on it later this month.
Its rejection raises the prospects of Britain leaving the bloc without an agreement, creating disruptions that threaten to hit the aviation industry hard.
London and Brussels are making contingency plans that will allow UK carriers to continue flying to EU countries even if there is no agreement on future trade and other rules. But it would only be a bare-bones deal that does not allow UK airlines to conduct intra-EU flights.