Ryanair has issued a warning to passengers travelling in the next few days, in an effort to manage the long waits at both check-in and airport security.
It comes following reports of huge queues forming at major airports, flight cancellations, and passengers left stranded or holidays cancelled last minute.
Ryanair has escaped from the current crisis at UK airports at the moment, unlike British Airways, TUI and EasyJet, who have all had to cancel hundreds of flights.
What has Ryanair said to passengers?
An email to customers read: "Please arrive at the airport three hours prior to the departure of your Ryanair flight as we are experiencing security delays at the airport.
"Please note, that our boarding gates close 30 minutes prior to the departure of your flight."
Holidaymakers are now being urged not to arrive at the airport more than three hours early, despite facing horrific five-hour queues that snake through terminals.
Pictures of long queues have been seen at airports everywhere from Bristol and Manchester to Gatwick and Heathrow.
There has also been chaos at train stations too, with footage taken at London’s St Pancras station showing huge queues for the Eurostar.
Travellers waited on pavements outside the station as a "technical issue" caused delays leaving London.
Ryanair has also recommended checking in baggage as early as possible.
According to the firm’s website, the ‘bag drop’ desks open two hours prior to the scheduled flight departure time.
The airline said: “The Bag Drop desks close strictly 40 minutes before the scheduled time of departure.
“If you miss this deadline your booking could be cancelled without refund and you could be prevented from boarding the plane.”
It added: “It’s important that you make it to your boarding gate in good time, at least 30 minutes before your flight departure time. Boarding closes 20 minutes before departure.
“Please have your valid travel document and boarding pass ready at the boarding gate.”
What airlines are cancelling flights?
TUI announced on Tuesday (31 May) that it was cancelling hundreds of flights next month.
It plans to scrap around 43 flights a week at Manchester Airport until 30 June.
The company said in a statement: "Due to the amount of on-going disruption in our operation at Manchester Airport, we have made the incredibly difficult decision to cancel six flights a day (43 flights a week), from Tuesday 31st May until Thursday 30th June.
“All other airports in the UK are planned to operate as normal."
The statement added: "We understand how disappointing this will be for those impacted; however, we believe this is necessary to provide stability and a better customer service at Manchester Airport."
Hundreds of flights with easyJet were also recently cancelled after the airline suffered from an IT glitch.
Meanwhile, British Airways has cancelled more than 100 flights - but these had been cancelled in advance as part of their schedule reduction until October.
The airline confirmed that 16,000 flights between March and October would be cancelled to prevent short-notice cancellations.