Flybe has blamed a shortage of pilots as one of the reasons after it cancelled dozens of flights.
The regional airline said a “combination of factors” caused the disruption on Wednesday.
Passengers travelling to and from Aberdeen, Belfast, Birmingham, Cardiff, London Southend and Southampton were among those whose travel plans were thrown into disarray.
The Exeter-based carrier said in a statement: “Flybe sincerely apologises to all our customers and partners affected by the current flight cancellations.
“Whilst 95% of Flybe flights are operating as per normal, we do recognise the impact of today’s cancellations.
“We are doing our best to mitigate the impact of the current situation that has arisen due to a combination of factors including seasonality, pilots’ end of leave year, Easter holidays, base restructuring and the shortage of pilots across the industry that Flybe has highlighted over recent months.”
Editor of Which? Travel magazine, Rory Boland, said: “Thousands of people will understandably be frustrated to have their travel plans thrown into chaos by these last-minute cancellations.
“The lack of clear information provided by Flybe was completely unacceptable.
“All passengers affected by these cancellations are entitled to a full refund or to be rerouted on to another flight to their intended destination – and to over £200 compensation under European air travel rules.”
Pilots’ union Balpa said it has learned that Flybe is to close its bases at Cardiff and Doncaster Sheffield, and scale back its operations at Exeter.
Flybe flies 8.5 million passengers each year to 170 European destinations.
In February the airline was bought by a consortium led by Virgin Atlantic following poor financial results.
Connect Airways, which consists of Virgin Atlantic, Stobart Group and Cyrus Capital, paid £2.8 million for Flybe’s assets and operations.