Photo: Contributed

Ryanair has made the biggest-ever order of Boeing planes by a European airline, announcing Tuesday it will buy 175 aircraft in a major boost for the U.S. aerospace giant.

Neither side disclosed the purchase price for the 737-800s, but budget carrier Ryanair said it did negotiate a bulk discount off the total list price of $15.6 billion. Industry analysts said Ryanair almost certainly was paying less than half price, meaning a total bill below $8 billion, or $45 million per aircraft.

Ryanair Chief Executive Michael O'Leary and the head of Boeing's commercial airplanes division, Ray Conner, signed the agreement Tuesday in New York.

The deal was timed to coincide with Tuesday's visit by Irish Prime Minister Enda Kenny to Washington, D.C. to meet President Obama and senior American legislators for St. Patrick's Day-related events. Kenny plans to visit Seattle and Washington State, the base for Boeing operations in the Pacific Northwest, later this week.

The move also takes the sting away from Boeing's loss of a big order on Monday, when Indonesia's Lion Air gave Boeing rival Airbus an order for more than 200 single-aisle planes.

Ryanair already operates a fleet of 305 Boeing 737-800 Next Generation aircraft. It is Boeing's biggest European customer for the model, which launched in 1997 and faces global competition from the Airbus A320. Both are single-aisle aircraft with cabins that typically carry 150 to 200 passengers.

Boeing's primary 737 assembly line in Renton, Washington, faces a transition to building a newer model called the 737 MAX by 2017. Ryanair's order represents about a half-year of full-time work for the plant.