Jet2.com has temporarily ceased flying from Belfast international airport due to what is says are increased safety concerns during runway maintenance.
Flights to Leeds Bradford have been switched to fly from George Best Belfast city airport, while a flight to Tenerife due to leave this morning was switched to depart from the city of Derry airport.
Belfast international said it was investigating Jet2’s concerns, but no other airline has reported any issues.
The airport said one Jet2 aircraft has reported engine-related problems on three occasions, but there is no conclusive evidence connecting this with the runway.
The Civil Aviation Authority has said it is confident Belfast international airport is safe to operate.
A programme to re-surface a runway has been disrupted because of recent weather.
Jet2.com is due to make a further announcement later this week about international flights.
Managing director Ian Doubtfire told BBC News: “We took the difficult decision to cease operations at Belfast international airport at midnight on Sunday April 7 2013.
“Our domestic flights operating on Monday April 8 between Belfast and Leeds will operate from Belfast city airport. All passengers on these flights should either check in at Belfast international or head straight to Belfast city airport.
“We would like to apologise for any inconvenience this may cause, however, the safety of our customers is of paramount importance and we will not operate from Belfast international airport until we have reassurances on the runway maintenance.”
The airport said passenger safety was a priority and it had an exemplary record.
“We can confirm that we are engaged in an extensive runway re-surfacing project at Belfast International, but the unseasonal weather has prevented any substantive work taking place for almost three weeks,” it said.
“During this down-time, one Jet2 aircraft has been reported as exhibiting engine-related problems on three occasions.
“No other airline, nor indeed any other Jet2 aircraft or aircraft of this type, has reported any similar issue. A full investigation is under way to assess what actually occurred.”