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 today.
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 €3.3 million for Flybe’s assets and operations.
Ten Flybe flights cancelled at Belfast City Airport as airline blames pilot shortage
Ten Flybe flights in and out of Belfast City Airport have been cancelled.
An industry-wide shortage of pilots was partially blamed for today's disruption by the company.
Flights affected include services to Birmingham, and round trips to and from Leeds Bradford and Aberdeen.
A flight from East Midlands was also cancelled.
A statement by the airline said: "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.
"We have already identified several mitigation actions and will be issuing further updates throughout the day.
"All those affected have been emailed and advised they can re-book for travel on an alternative flight or apply for a full refund."
Passengers received texts and emails on Tuesday evening telling them of problems with their flights.
The disruption followed the launch of the airline's summer schedule.
Flybe was recently bought by the Connect Airways consortium, which includes Virgin Atlantic.