Ryanair could speed up share buybacks to comply with European Union ownership laws as a result of Britain leaving the EU, the Irish carrier's chief executive said on Tuesday.

To qualify as an EU airline carriers have to be majority owned by EU investors. Ryanair was 53.6 percent owned by EU nationals, including UK investors in 2016, according to the airline.

And Michael O'Leary said around 20 percent of Ryanair's shareholders are UK-based. The carrier has already been carrying out share buybacks to return cash to shareholders.

"Ownership post Brexit is a real issue," O'Leary told a hearing in the European Parliament. "It might help me to accelerate the share buyback if UK shareholders are forced to sell."

Like other European airlines, Ryanair has clauses in its articles of association that mean it can force non-EU shareholders to sell their shares in order to ensure that EU investors retain the majority.

He reiterated concerns that unless a deal is agreed for Brexit then flights between Britain and the remaining EU 27 countries could be grounded.

"There is not a legal mechanism on which airlines can operate in a 'hard Brexit, no deal' outcome. There will simply be no flights," he said, adding that Ryanair would start cancelling flights six months before the March 2019 date when Britain is due to leave the EU with or without a deal.

Aviation is not covered by World Trade Organisation rules which would apply to other industries should Britain fail to agree a deal by March 2019.

Willie Walsh, CEO of British Airways parent IAG, said he did not agree with O'Leary's assessment and that he believed there would be a solution. He called on the UK to agree a liberal air transport agreement with the EU.

One suggestion is that in the absence of a deal on aviation by March 2019 EU national governments could revert to the old bilateral agreements with the UK governing air traffic rights. O'Leary said, however, that individual EU member states were unlikely to be allowed to negotiate bilaterals independently.