Jet2 planes from the UK to Spain turned back in mid-air as the airline announced it was cancelling all flights to the country amid the coronavirus outbreak.
New infections have risen sharply in Spain and the government put 60,000 people in four towns on a mandatory lockdown on Friday.
Prime Minister Pedro Sanchez said a two-week state of emergency will come into force as the death toll reached 120.
Jet2, which is based at nine UK airports and flies to destinations including Alicante, Malaga and Lanzarote, said it was cancelling all flights to mainland Spain, the Balearic Islands and the Canary Islands for at least the next seven days.
A spokeswoman for the airline confirmed that seven flights were in the air and turned back to the UK on Saturday morning.
A statement from Jet2 said: “In response to local measures introduced throughout Spain to prevent the spread of Covid-19, including the closure of bars, restaurants, shops and activities including any water sports, we have taken the decision to suspend flights for at least the next seven days to Mainland Spain, the Balearic Islands and the Canary Islands with immediate effect.
“We know these local measures will have a significant impact on our customers’ holidays which is why we have taken this decision.
“We are contacting our customers who are currently in these destinations, and who are due to travel, to advise them of their options, so we urge customers not to call us.
“This is a fast-moving and complex situation and we are reviewing our programme as a matter of urgency, so that we can fly customers back to the UK.
“The health and safety of our customers is our number one priority, and we would like to thank our customers for their understanding.”
The Foreign and Commonwealth Office updated its travel advice for Spain on Friday, advising against all but essential travel to the regions that the Spanish Ministry of Health has designated as areas of community transmission: Madrid and La Rioja, and the municipalities of La Bastida and Vitoria (both in the Basque Country) and Miranda de Ebro (in Castilla y Leon).
Meanwhile, LOT Polish Airlines, which flies to UK airports including Heathrow, Edinburgh and Nottingham, has suspended all connections from both Poland and Hungary for a period of 10 days from March 15.
Rory Boland, editor of Which? Travel, said: “Airlines cancelling flights to Spain will be worrying for customers, particularly those already in the country, who will urgently need clear information about support they will be offered and plans to ensure they get home safely.
“Passengers of all airlines will have questions about what this means for their upcoming trips, especially with the FCO already warning against travel to some parts of Spain, and the government and airlines should work as quickly as possible to clarify the situation for holidaymakers.
“The CAA must also monitor the situation closely to ensure airlines are fulfilling all their legal obligations to passengers when flights are disrupted, so that we don’t see a repeat of the situation in Italy where passengers were left stranded.”