Ryanair chief executive Michael O’Leary repeated his warning this week of a halt to all UK-EU flights for a period in 2019 without a deal on flying rights.

“There is a real prospect in summer 2019 there will be no flights,” he said. “The British underestimate the extent to which voices in Europe are lobbying against UK flights.

“There is increasing awareness in Brussels that aviation will be a way to stick it to Britain. They are going to [threaten to] ground you for a couple of months to put pressure on you.”

O’Leary was honest enough to admit: “I’m being hysterical, but this is the legal position.”

And he conceded: “I don’t really think there will be disruption, only because the UK government will be panicked into an interim agreement.”

This is lobbying Ryanair style, when the aviation industry’s general preference is to lobby by stealth and apply pressure in private.

So other carriers have kept quiet on the issue, preferring the line taken by UK airlines lobby group Airlines UK – of which Ryanair became a member this week.

Tim Alderslade, Airlines UK chief executive, responded to O’Leary’s warnings of disruption by insisting: “We’re entirely confident about the [UK] government’s engagement with this.

“Connectivity is so important to the UK and to the 27 EU states. There is a huge flow of Brits to Southern Europe [and] they don’t want to see that connectivity come to a halt.

“It’s a technical issue that needs to be addressed, [but] we are not even at the negotiating stage yet.”

However, this isn’t the whole picture. O’Leary’s view was confirmed by a confidential document submitted to the British government last month by the UK’s leading airports and their owners, representing the views of Heathrow, Gatwick, Manchester, Stansted and London City.

This forecast “a catastrophic slump in British air travel” without a deal on open skies.

In its most doom-laden scenario the report, entitled ‘Brexit and the aviation industry: the opportunity for certainty’, forecast a fall of 41% in passengers or 8.1 million bookings between March 2018 and March 2019.

It pointed out: “Airlines, passengers and airports have to plan months if not years in advance.” So without a deal, the nearer the industry gets to British withdrawal “the greater the negative consequences will be”.

This is O’Leary’s point exactly.

Ryanair threatens to pull out of places – and on occasion does so – fairly routinely. It is how the carrier negotiates with regional airports.

The airline is not about to pull out of the UK. It’s Europe’s biggest aviation market. However, Ryanair might move some aircraft and drop its handful of UK domestic routes if it isn’t satisfied with an agreement or assurances of an agreement by autumn next year.

But O’Leary’s assessment of the risk is right, as is his appreciation of the lobbying behind the scenes by EU airline rivals.

UK carriers no doubt recognise the same risk, but choose not to say so for fear of hitting passenger demand. O’Leary doesn’t care because he reckons Ryanair can’t lose.

If demand falls his flights will still be cheaper. If there is no deal, Ryanair would still be able to fly across the EU. EasyJet and British Airways would not.

But where might confirmation of O’Leary’s view, in the form of that confidential airports’ report, have come from?

The government would hardly have leaked it. Although a pro-Brexit civil servant might have done so, it is more likely to have come from the airports’ side.

I would be surprised if Heathrow was responsible. The airport is too close to British Airways and IAG chief Willie Walsh.

It is unlikely to have come from Gatwick, which has exceeded Ryanair in self-promotion in recent years. The story is not positive or about Gatwick.

I would also rule out London City, the corporate travellers’ airport of choice.

That leaves the Manchester Airport Group (MAG), which owns Manchester and Stansted. The latter is Ryanair’s principal UK base, of course.

Perhaps we need look no further.