Irish low-cost airline Ryanair announced a deal today to buy 100 jets from the U.S.-based jet manufacturer, in a deal valued at around $11 billion. If all goes well, Ryanair will have the option to buy 100 more jets from Boeing (BA). Rumors of the deal were originally reported last week.

The new planes will have 197 seats, 11 more than Ryanair’s current fleet of 737s. More seats allows Ryanair to maximize profit, while staying below 200 passengers means the airline won’t have to put an extra flight attendant on each plane. But, passengers shouldn’t fear for lost legroom — the new seats are smaller, so there’s actually a bit more room to kick around.

The purchase is consistent with Ryanair’s desire to expand to 500 aircraft by 2024, said Jonathan Wober, an analyst with the CAPA Centre for Aviation.

He also noted that Ryanair is notoriously scrupulous about getting the best discount possible for the aircraft the purchase. The total discount wasn’t disclosed, but Wober noted that “it seems likely they’ve got good terms.”

The jets being purchased are the newly designed Boeing 737 MAX 200 planes. In addition to accommodating up to 200 seats, the planes have 20% better fuel efficiency than 737s currently operating. Ryanair announced that the planes will reduce fuel consumption by up to 80% and also reduce noise emissions by 40%.

Myles Walteron, a Boeing analyst at Deutsche Bank, said this move, coupled with an earlier purchase of older model 737s by Ryanair, is a sign Boeing likely doesn’t have to worry about being challenged by rival Airbus for low-cost carrier business.