Grayling told the Airport Operators Association’s (AOA) annual conference that tourism and trade links meant there was no chance of flights being grounded in March 2019, even if new air services agreements have not been renegotiated by then.

But he stopped short of telling tour operators not to mention potential Brexit disruption in their terms and conditions.

Grayling acknowledged that airlines and operators created schedules a year in advance, leaving only a few months for the government to reassure them that summer 2019 plans would not be disrupted.

“I think it is a big leap to believe that the Spanish government will not want the UK to fly there in summer 2019. It is inconceivable that the planes will stop flying. It is not going to happen,” added Grayling.

“It is not for me to tell companies what to put in their contracts. But I see no circumstances whereby planes will not be able to fly after 2018.”

Aviation bosses appearing before MPs on the Transport Committee this week were similarly confident that flights would not be grounded by Brexit, even without a transitional deal between the UK and EU.

John Holland-Kaye, chief executive of Heathrow, said: “From an EU point of view, it is just as much in their interests to have continuity after Brexit as it is for us.

“For places like Spain, it’s inconceivable that they would want to have any discontinuity.”

Willie Walsh, chief executive of British Airways’ parent company International Airlines Group, added: “I’m pretty confident that there will be an arrangement put in place. The prospect of there being no flying between the UK and Europe, I don’t agree with that at all.”

Grayling confirmed during his AOA appearance that the government had been having “informal discussions” with other countries over post-Brexit aviation arrangements.

And shadow transport secretary Andy McDonald called for aviation to be dealt with separately from the main Brexit negotiations.

“We have a government that is basically saying ‘it’ll be all right on the night’,” he said. “We are not being informed. We are just being given some bland assurances that all will be well.”

Tim Hawkins, corporate affairs director of Manchester Airports Group, called for a new aviation deal to be reached quickly. He told MPs: “The earlier confidence can be created for passengers and airlines, the better.”