American Airlines on Wednesday became the first major U.S. airline to order Airbus' new long-range, single aisle aircraft with a commitment to buy 50 planes. 

The deal for the A321XLR jetliners, announced at the Paris Air Show on Wednesday, marks the first major American carrier to purchase the European planes since their debut Monday. American is converting its previous order for Airbus' A321neos into an order for the larger and more capable A321XLR planes.

Neither American Airlines nor Airbus would disclose the financial terms of the deal, but American Airlines President Robert Isom says the XLR will initially cost the airline more than the A321neo.

"My feeling is this aircraft certainly gives us much greater utility in the long run and at the end of the day will be worth quite bit more to us," Isom said in a video discussing the deal released by American Airlines.

The XLR is expected to open more routes between the U.S. and smaller, secondary cities in Europe. For example, American could potentially fly the XLR between Philadelphia and Basel, Switzerland. "This opportunity, with the enhancements being made to the XLR are really cool," said Isom.

Since Airbus launched the new plane Monday, the company has racked up eight orders for more than 160 XLR's. Air Lease Corporation, which leases hundreds of airplanes to airlines around the world, placed the initial order for 27 XLR's. CEO John Plueger told CNBC the plane is "a blockbuster."

American is the first U.S.-based airline to order the newest Airbus plane, but Denver based Frontier Airlines will also be flying the XLR shortly after deliveries begin in 2023. Frontier's parent company Indigo Partners placed an order for 50 XLR planes, with initial plans to put 18 of them into Frontier's fleet.

The A321XLR is expected to be used on longer routes where there aren't enough travelers to support the regular use of a larger twin-aisle plane.

— CNBC's Meghan Reeder contributed to this report.