Most holidaymakers stranded in Spain following a 24-hour wildcat strike by air traffic controllers have now arrived home to the UK.
The staff began their unofficial action on Friday in a row over pay and conditions, causing the Spanish government to declare a state of alarm which will be in place for the next two weeks.
Workers returned to their shifts on Saturday night after being threatened with jail, but officials said it could be days for flights to return to normal. Dozens of services to and from UK airports were grounded as Spanish air space was closed, with Ryanair, easyJet and Iberia all cancelling flights.
Transport Secretary Philip Hammond said there had been no advance warning of the strikes, which left hundreds of thousands of tourists, many of them British, stranded.
Association of British Travel Agents (Abta) spokesman Sean Tipton said: "There is still a backlog. Things are getting back to normal but if anyone has a flight on Monday they should check with their travel provider.
"I would say the majority of people are back now. Airlines have made it a priority to get them back. As it's a quiet time of year, there has been more availability."
The Foreign Office has changed its travel advice on Spain, urging people to check with their airline or travel operator before setting off to the airport.
A message on its website reads: "Although latest reports suggest that some air controllers are slowly returning to work and some flights are resuming, we strongly advise anyone planning to fly this weekend or on Monday, either to or from Spain, to contact their airline or travel operator before travelling to the airport."
The industrial action came in the week that cold weather had caused transport systems in the UK to grind to a halt, closing some airports.
On Sunday, flights were delayed and cancelled at Gatwick, Heathrow, Manchester and Liverpool John Lennon Airport.