Nearly six months after arch-rival Airbus announced a new long-range version of its A321 (the A321LR) with an order of 30 planes from launch customer Air Lease Corp. (NYSE: AL), Boeing Co. (NYSE: BA) has decided that there is, indeed, demand for a medium range jet to snuggle into the gap between the single-aisle 737 and the dual-aisle 787 Dreamliner. The company has not yet decided to build such a plane, but at least it now admits that it is worth exploring the possibility.

Boeing’s 757, which went out of production in 2005, flew what the industry calls long, thin routes, carrying around 200 passengers distances of around 4,000 to 5,000 nautical miles. United and American both operate 757s across the Atlantic, and the longest commercial flight currently flown by the 757 connects New York non-stop with Berlin, a distance of slightly more than 4,000 nautical miles. The 757 can only fly this far with fewer than 190 passengers.

The 757 replacement plane is also often referred to as the Middle of the Market (MOM) aircraft. Boeing had hoped to compete against the A321LR with its 737 MAX 9, but that idea has gotten no traction in the market.

Fortunately for Boeing even the Airbus A321LR has some problems. United Airlines believes the plane’s capacity is too small. United’s 757s fly 169 passengers and American’s planes are set-up to fly 179 passengers, compared with 164 for the A321LR.

Boeing’s vice president of global sales has said that the company’s customers are interested in a plane that carries 250 passengers on routes of five to nine hours, according to a report at The Wall Street Journal. The 787-9 has a capacity of 250 to 290 and the 787-10 is even larger. And the range is much longer than needed. That adds up to planes that cost too much. Even the 787-8, with a capacity ranging from 210 to 250, has a specified minimum range of 7,650 nautical miles, a third more than the long, thin routes the 757 serves.

ALSO READ: How Boeing and Airbus May Fight Harder for Fewer Air Show Orders

When Airbus launched its A321LR in January it saw a market size of about 1,000, evenly divided between new planes and replacements for the 757. Boeing has not yet said how big it thinks the market for the replacement might be, but the company built 1,050 of the original.

Airbus expects to have the A321LR enter service in 2019, and it is difficult to see how Boeing could do better than a year or even two later, even if the company went with a variant to an existing model. A clean-sheet design could take even longer.

Thank you for reading! Have some feedback for us?
Contact the 24/7 Wall St. editorial team.