Thousands of travellers have been hit by delays and cancellations at airports across the UK, and issues could be set to last for days.

Travel delays started on Monday after a UK air traffic control failure, meaning flight plans had to be input manually by controllers.

On Monday, 790 flights departing UK airports were cancelled, as well as 785 arriving flights, according to aviation analytics firm Cirium.

This equates to about 27% of all expected departures and 27% of expected arrivals, Cirium added.

Transport Secretary Mark Harper told GB News it was the worst incident of its kind in “nearly a decade” and announced an “independent review” will be carried out.

The disruption has continued into Tuesday, and Heathrow Airport said in a statement: “Schedules continue to be affected by yesterday’s restrictions on UK airspace.

“While the majority of passengers will still be able to travel, there will unfortunately be some disruption on some routes, including flight cancellations.”

Here’s what passengers need to know about the travel chaos.

Cancellations or delays

“You have the right to choose between a refund to your ticket or to be rerouted,” Rory Boland, editor of Which? Travel, told PA news agency.

“So if you’re due to travel out in the next day or two and this disruption is putting you off and your flight has been cancelled, you can decide to cut loose and claim your refund.”

The scenario will likely be different for anyone who is stuck abroad or needs to travel.

Boland stressed it’s your legal right to be rerouted “at the earliest opportunity”.

He added: “That can mean on the same airline if that’s possible, but it can also mean with a rival airline, or via different routes if they can fly you via a hub to where you’re going.

“What we’re seeing today and what we’ve seen with other periods of disruption is the airlines routinely ignore this rule, or you have to be very insistent to get them to act upon it.”

Boland said there have been instances of airlines booking stranded passengers onto a flight up to a week later.

“That’s not on, and you should go back and challenge the airline about that. If you find an alternate airline can get you home earlier – whether that’s a matter of hours or a couple of days earlier – you should go to your airline, tell them and if they refuse to rebook, you should do it yourself if you have the money and claim it back from them.”

If you’re stranded at the airport

The Civil Aviation Authority (CAA) website says airlines are obliged to support passengers who are affected. This means anyone whose flight has been delayed or cancelled from a UK airport, arriving in the country on an EU or UK airline, or arriving at an EU airport on a UK airline.

Passengers are eligible for support if they are affected by a “significant delay” – more than two hours for a short-haul flight of under 1,500km, more than three hours for medium-haul of up to 3,500km, and more than four hours for long-haul flights.

Airlines must provide a reasonable amount of food and drink (normally in the form of vouchers), refunds for the cost of calls and accommodation for passengers stuck overnight and transport to a hotel or their home. This must be provided until you are able to fly, no matter how long the delay lasts.

Boland called this “a fantastic law in theory, but in practice it can be difficult”.

He said: “What you may find is that there are no airline staff to ask about accommodation, you can’t get in touch with them on the phone and you don’t know what’s going on – that doesn’t change your right.”

If you’re stranded overnight, “You can book yourself accommodation and claim it back”, he advised – as long as it is “reasonable”, and not a luxury stay.

Getting access to lounges

If you’re stranded at the airport, you might want to make the wait a bit more comfortable in a lounge.

Boland said: “Don’t assume going into the airport lounge will necessarily be a bastion of peace and quiet. They’ve been really busy the last couple of years, so if you can, sneak a peek inside first before you pay.”

Many lounges will take one-off payments for access, and Boland recommends checking your credit card or insurance providers, as some have “free perks” such as lounge access included.

If you’re signed up to the O2 network and your flight is delayed by 60 minutes or more, you can get complimentary access to 1,200 airport lounges in over 500 airports through the SmartDelay scheme.

Making claims

Boland said it can be “difficult to claim money back in terms of how long it takes – you have to file paperwork with the airline, [and] they often drag their heels”.

Claims should be made through the airline you booked with.

“Some airlines won’t respond in due course, it will be a painful process,” he said.

“If it does take too long, they refuse you and you don’t think they’re right, or they’re just ignoring you”, Boland recommends going to alternative dispute resolution (ADR).

“All of the airlines are required and signed up to these third-party ADR bodies… You supply your information, the airline supplies their information and they decide whether your expenses or compensation should be paid out.”

If you’re flying this week

Boland said: “Things do look like they’re getting better and should continue to get better quite quickly” – but there might still be disruptions this week.

“If you’re travelling immediately, the best advice is not to go straight to the airport, but do as the airlines are saying, which is check ahead of time if the flight is operating,” he added.

“I often find information from the airport is actually easier for customers to access – you can look at the arrivals and departures board and see what’s going on with your flight.”