Aer Lingus is "very keen to see" whether the Airbus A321neo or Boeing 737-9 Max will offer the range needed to enable it to deploy the aircraft on some of its transatlantic services.
If so, the carrier could order up to five re-engined narrowbodies to serve the USA's east coast as part of a larger short-haul fleet renewal programme.
In an interview with Flightglobal, Aer Lingus chief commercial officer Stephen Kavanagh said the carrier is looking at the Neo and Max families and "part of that evaluation will be whether the A321neo or the 737-9 Max would have transatlantic capability".
If the aircraft do offer sufficient range, Aer Lingus could order "up to five" re-engined narrowbodies to "complement" its widebody flights from Belfast, Cork and Shannon to Boston, Chicago and New York by offering additional frequencies, said Kavanagh.
"The geographical location of Ireland on the edge of Europe is advantageous and it should be in range. We're very interested in exploring this option to complement our widebody operations."
He added that any potential order would not affect Aer Lingus's existing order for nine Airbus A350s.
Aer Lingus's evaluation of the Neo and Max families is also focused on eventually replacing its short-haul fleet of 36 A320s, said Kavanagh.
"Within 12 months we will complete our evaluations and enter negotiations with the manufacturers," he added.
US Airways last year informed Airbus that it was interested in an A321neo capable of operating long-haul flights to Europe and Hawaii, as a more fuel-efficient alternative to Boeing 757s.
Airbus has previously given a range figure of 3,720nm (6,890km) for the A321neo, while Boeing insisted earlier this month that the 737 Max family would equal, or better, its rival's range.