AER Lingus and Etihad have tightened their links further after US authorities approved a codeshare between the airlines for transatlantic flights.
The move will allow Etihad to market flights to the US where passengers will travel on Aer Lingus services from Dublin to US cities.
Etihad owns a 3pc stake in Aer Lingus. Its 'EY' flight code will be added to the flights.
Under the plan, Etihad will offer 30 joint operations via Dublin to Boston, New York and Chicago a week.
The move gives Etihad passengers the ability to clear US Customs and Border Protection in Ireland. That means they will be able to arrive in the US effectively as domestic passengers – a key attraction for Aer Lingus as a code share partner.
Aer Lingus chief commercial officer Stephen Kavanagh said: "Customers connecting from Etihad Airways' network onto Aer Lingus flights at Dublin will enjoy a seamless transfer and will be able to avail of Dublin's US pre-clearance facilities."
Etihad already places its 'EY' flight code on Aer Lingus flights between numerous destinations in the UK and Ireland.
In return, Aer Lingus has its 'EI' flight code on services operated by Etihad Airways between Abu Dhabi and Dublin, Bahrain, Kuala Lumpur, London, Manchester, Melbourne, Muscat and Sydney.
News of the code share deal came as Etihad revealed record sales for the first quarter. The carrier posted a 19pc increase in first-quarter passenger revenue to $900m (€700m), while turnover from its cargo business climbed 17pc to $193m.
Etihad's Irish chief executive James Hogan said his group had "outstripped global trends" so far this year.