The UK must remain in the EU to reduce the number of strikes by air traffic controllers (ATC) on the continent, Ryanair boss Michael O'Leary has said.
He insisted that the good aspects of Britain's EU membership - such as the single market - "far outweigh the bad".
Speaking at a press conference at Ryanair's headquarters in Dublin, Mr O'Leary said: "The only way to reform the bad - such as French ATC strikes, such as that kind of shambles - is to keep Britain in Europe working with some of the more sensible countries like the Italians, the eastern European countries.
"(We must) deal with some of the idiotic members of the European Union, for instance the French, who believe that nobody should work and the Germans will pay for everybody."
Hundreds of flights across Europe were disrupted when French ATC went on strike in the days building up to Easter. Mr O'Leary said it was the 43rd such action since 2009 and called for ATC strikes to be banned.
He predicted that opponents of Brexit will have to campaign "very hard" in the build-up to the June 23 vote.
"I think it's vital for the UK economy that the UK stays in," he said.
"The more it looks like (the campaign to remain) will lose, the more companies, big employers, big foreign investors in the UK like Ryanair, will campaign much harder to stay in.
"A bit like the Scottish independence referendum last year. In the last couple of days where it looked like it might be lost, companies suddenly woke up and said, 'listen, we're moving to London if you guys vote for independence'."
Mr O'Leary added that the airline will invest less money in Britain if voters back Brexit.