THE chief executive of the company which owns Glasgow and Aberdeen airports has warned of flights being grounded and airlines going bust in the event of a no-deal Brexit.

Flights in and out of Scotland are currently governed by 155 international flying agreements which the UK has in place with countries around the world, with 44 falling under the European Commission’s Single European Sky directive.

The 44 agreements covered by the regulation, which effectively allows airlines to fly between the UK and other EU countries, account for 85 per cent of the flights in and out of the UK.

But the country will fall out of those agreements by the Brexit date of March 29 next year - if a new agreement is not reached with Brussels.

Derek Provan, the chief executive of AGS Airports, warned that a no-deal Brexit will lead to planes being grounded in Glasgow, Aberdeen and other UK airports.

Asked to define the worst-case scenario from a disorderly Brexit, Mr Provan likened the situation to 2011, when hundreds of flights in Europe were cancelled because of the vast ash clouds created by an Icelandic volcano.

In a wide-ranging interview with The Herald, the former chief operating officer of Heathrow Airport said: “Eighty-five per cent of the flights fly in and out of Europe. What that would mean is aircraft on the ground, aircraft physically unable to take off because they don’t have any air space to fly into, because you don’t have an agreement for that aircraft to fly through that air space.

“So, you would be talking about 85% of your schedule sitting on the ground until such times an agreement would be made.

“It would be similar to the volcanic as scenario, only you are planning it, which seems incredulous.”

Mr Provan’s comments come as the UK Government issues a series of technical notices advising people and businesses how to prepare for a no-deal Brexit.

Notices for the aviation sector are expected to be issued imminently.

With Ryanair having previously stated it will pull flights from the UK in the eventuality of a hard Brexit, Mr Provan expressed dismay that the UK was hurtling towards that scenario. He said: “How long would that last? Who knows?

“If you had asked me four months ago I’d have said it wouldn’t last a day, because the scenario would never happen.”

He added: “There is no mitigation against no deal, however long that takes place. Unless you have got an agreement that sits within there, at this moment in time we don’t understand what those mechanisms would be to allow aircraft to fly.

“The UK Government has been very clear that aviation is a priority, but that is not what we are seeing.”

The airport chief, who is also concerned about the UK losing its place in the European Aviation Safety Agency (EASA), said AGS maintains regular dialogue with UK Government officials.

The most recent meeting, which took place around one month ago, did not give him confidence a deal was likely.

Mr Provan, whose company employs 1,000 staff, said: “Now we are being advised that is what we should be planning for.

“It would mean aircraft on the ground until such times there is an agreement.”

As well as the risk of plans being grounded, Mr Provan, who succeeded Amanda McMillan at the helm of AGS in January, said there is a risk the airlines could go to the wall if new flying agreements are not stuck before the official Brexit date of March 29, 2019.

He said: “Most airlines are operating with very tight business margins, so they would survive for days or weeks at maximum.

“They wouldn’t survive any longer than that.”