European discount airline Ryanair (NASDAQ:RYAAY) ordered an additional 75 Boeing (NYSE:BA) 737 MAX jets on Thursday, a strong sign of confidence in an airplane following the plane's 20-month safety ban.

The order, at list price, is worth about $9 billion, but Ryanair likely was able to negotiate a significant discount. The Irish budget airline is one of Boeing's biggest customers, and now has 210 737 MAX planes on order.

A 737 MAX in Ryanair colors.

Image source: Boeing.

The 737 MAX was grounded in March 2019 after a pair of fatal accidents, and Boeing only won recertification for the plane to fly again last month. The order is a big boost for the program, which at one time was expected to be one of the best selling jets of all time but now face a difficult relaunch.

"Ryanair's board and people are confident that our customers will love these new aircraft," Ryanair CEO Michael O'Leary said in a statement announcing the order . "Passengers will enjoy the new interiors, more generous leg room, lower fuel consumption and quieter noise performance."

Boeing CEO Dave Calhoun said his company is "gratified that Ryanair is once again placing its confidence in the Boeing 737 family," and reiterated he believes the plane is safe.

"Boeing remains focused on safely returning the full 737 fleet to service and on delivering the backlog of airplanes to Ryanair and our other customers," Calhoun said. "We firmly believe in this airplane, and we will continue the work to re-earn the trust of all of our customers."

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.