Ryanair has agreed a $40bn (£31bn) deal with Boeing that will see it purchase up to 300 new aircraft over the next decade.
Half of the 737-MAX-10 order has been described as firm, with the remaining being options.
The airline claims this is the largest order ever placed by an Irish company for US manufactured goods.
Phased deliveries will start in 2027 and run until 2033, with half of the new purchases set to replace older aircraft in the Ryanair fleet, boosting efficiency and cutting emissions.
The new aircraft, which have 228 seats, are to be used to meet Ryanair’s traffic which it forecasts will grow by 80% and reach 300m passengers a year by 2034.
The airline’s chief executive Michael O’Leary described the deal as “the ideal growth aircraft order for Ryanair, our passengers, our people and our shareholders”.
“These new, fuel efficient, greener technology aircraft offer 21% more seats, burn 20% less fuel and are 50% quieter than our B737-NGs,” he said.
He added that the deal would enable Ryanair to create more than 10,000 new high-paid jobs for pilots, cabin crew and engineers.
Given the size and scale of the transaction, it will be subject to shareholder approval at Ryanair’s next annual general meeting.
Boeing’s president and chief executive, Dave Calhoun, said the Boeing-Ryanair partnership is “one of the most productive in commercial aviation history”.
He said it enabled both companies to succeed and expanded affordable travel for the public.
“Nearly a quarter century after our companies signed our first direct airplane purchase, this landmark deal will further strengthen our partnership,” he added.
“We are committed to delivering for Ryanair and helping Europe’s largest airline group achieve its goals by offering its customers the lowest fares in Europe.”