Irish premier Leo Varadkar is "wrong" to suggest British aircraft would be barred from his country's airspace in the event of a no-deal Brexit, Downing Street has said.
So-called "overflight rights" are guaranteed by international treaties rather than EU membership, a Number 10 spokeswoman said after the Taoiseach claimed a hard departure by the UK would mean "planes would not fly".
The spokeswoman said the UK was confident of reaching a deal that included "aviation access" but added: "It's wrong to claim that Ireland could simply stop the UK from flying over its land as a result of Brexit.
"The reason we say that is because overflight rights are not guaranteed by the EU, rather by multilateral treaty which both ourselves and Ireland have signed up to."
Speaking in Co Kerry on Wednesday, Mr Varadkar said a no-deal Brexit would see Britain leave the Single European Sky programme, which co-ordinates flights, adding: "If they want their planes to fly over our sky, they would need to take that into account."
He added: "The situation at the moment is that the UK is part of the Single European Sky and if they leave the EU they are not.
"And that does mean if there was a no-deal hard Brexit next March, the planes would not fly and Britain would be an island in many ways - and that is something they need to think about."