Tomorrow morning's 8am Aer Lingus flight from Heathrow to Dublin, EI149, has been cancelled because of air traffic control staffing problems in London.
It is understood Aer Lingus is contacting affected passengers with a view to accommodating them on other flights.
A number of flights into Dublin Airport from Heathrow have experienced delays also.
Siobhan Moore of the Dublin Airport Authority said Aer Lingus and BMI are the only airlines affected.
DAA advised passengers to contact their airlines.
DAA spokeswoman Nicola Rochford added that because of the staffing issues there have been slot restrictions at Heathrow causing delays to two Aer Lingus flights departing Dublin and to one Dublin-bound flight.
