Aer Lingus A319 EI-EPT operated EI34 Belfast City – London Heathrow this afternoon, however the return EI35 was cancelled due to a technical issue with the aircraft. A320 EI-DEF positioned to Belfast City to operate EI36 Belfast City – London Heathrow and EI-EPT was able to return to traffic operating EI37 London Heathrow – Belfast City.