Holidaymakers were stuck in Ibiza in Spain after a firefighting plane blocked the runway while landing.
More than 20 flights to and from the island were cancelled and 17 diverted to other airports including Barcelona and Majorca on Sunday.
Firefighters were called to remove the plane that was causing the problems, about an hour after it suffered an accident while landing at around 4pm local time.
British holidaymakers were among those affected by the incident, which saw many sleep on the floor of the airport overnight, waiting for flights in the morning.
"Ryanair are useless! Over 12 hours delayed, spent the night on Ibiza airport floor! No information other than a few text and changing display boards!" Alisa Hall wrote on Twitter.
Did you get caught up in the chaos? Email webtravel@reachplc.com
"Had the best holiday but this is ridiculous!!!!"
Carly Loveridge, who took to Twitter to complain, added: "Ryanair any idea when you are going to stop delaying our flight?
"Can't find anyone to help us, we have been stuck in Ibiza airport overnight as we were told the flight would leave at 7.55am and now it's 10.35."
Karen Freakley added: "British Airways where are you in Ibiza airport? Flight delayed overnight. No information, no staff."
British travel enthusiast Jamie Taylor described the situation in the aftermath of the accident as "chaos", adding: "Runway has now reopened following an incident but departure lounge and security closed.
"Check-in hall heaving with people with nowhere to go."
British Airways flight BA479 were among flights affected, with passengers due to board complaining no-one from the airline had provided guidance.
Flights from London Luton and London Gatwick are among those believed to have been diverted to Majorca's Palma Airport. It was not immediately clear how many flights to Ibiza from the UK had been diverted.
Tabitha Colenso described her experience at the airport as "terrible", saying in a dig at BA: "@BritishAirways. We were delayed by 7 hours and then the flight was cancelled. Communication has been appalling. We are still unclear about when our return flight is.... Communication is absolutely key. Where is yours?
Spanish airports authority Aena confirmed in the aftermath of the accident that the "runway (was) blocked by a firefighting plane at Ibiza Airport.
"Work is underway to remove it. Flights may be diverted to other airports. Check the state of your flight with your airline.
Spanish air traffic controllers, confirming they were managing the diversion of flights to Barcelona, Majorca and Ibiza, described it as a "very complicated day".
IBANAT, which operated the plane which sparked the chaos, said in a tweet after the runway was cleared: "We are happy to confirm that the pilot who suffered an accident while he was landing at Ibiza Airport was unharmed."
The live departures board for Ibiza Airport shows a number of flights delayed today, including late into the afternoon.
Ryanair has been contacted for comment.