US airlines are increasingly showing firm interest in Boeing’s middle-of-the-market aircraft concept, which could replace many of the 757s and 767s that they continue to fly.

Executives from bothDelta Air LinesandUnited Airlinesspoke positively of the programme, dubbed the “MoM” by some, as they look at their future aircraft needs in the roughly 200- to 260-seat segment at the ISTAT Americas conference in San Diego.

AirticketsONLINE

“It has a lot of merit and, if they decide to launch it, we’d be very interested in considering it,” said Andrew Levy, chief financial officer of Chicago-basedUnited, at the conference.

Daniel Pietrzak, managing director of fleet management atDelta, agrees with Levy’s comments and elaborates a bit on what the carrier needs. “Look at it as a 757-300 capacity mission to something like a 767-200 – obviously new technology but with the size and range,” he says.

BothDeltaandUnited, as well as their peerAmerican Airlines, operate large fleets of 757s and 767s that they use for transatlantic and longer domestic missions. Together, the three carriers operate 258 757-200 and -300s, and 164 767-300ERs and -400ERs, the Flight Fleets Analyzer shows.

All three US carriers have largely replaced their domestic 757s and 767s with Airbus A321s and Boeing 737-900ERs.

The support of bothDeltaandUnited, both of which are large Boeing operators, would be a big boost for the MoM programme.

EvenAlaska Airlines, which was an all-737 operator until it added the Airbus A320 family to its fleet with its December purchase ofVirgin America, could be interested in the MoM concept.

John Kirby, vice-president of capacity planning at the Seattle-based carrier, says he sees a need at Alaska for an aircraft with 190 to 210 seats with a 4,000nm (7,400km) to 4,500nm range in the future – specifications that also fit Boeing's planned 737 Max 10 in seating capacity but not in range.

TAKING SHAPE

The specifications of the potential Boeing MoM – or in the words of Air Lease executive chairman Steven Udvar-Hazy: “just call it a 797” – are beginning to take shape, airlines and lessors say at ISTAT.

The twin-aisle aircraft, something Levy confirms for the first time, will have two variants with around 225 to 260 seats and a range of 4,800nm to 5,200nm.

“We continue to study what that airplane would look like,” a spokesman for Boeing says on the MoM concept. “We’re having very productive conversations with our customers and firming up opportunities there.”

Aengus Kelly, chief executive of AerCap, raises some of the issues that Boeing faces in ensuring that the potential aircraft meets the needs of the wider market, and not just the US carriers.

“That’s the challenge they have to get it right – how do you fix that equation of meeting the mission capability of a global customer base, not just three airlines in North America,” he says at ISTAT. “It has to have global capability.”

For example, Kelly says a 40,000lb-thrust (180kt) aircraft would be good for some carriers but not all, while a 45,000lb-thrust aircraft could meet more of the market demand but would be more expensive.

Boeing has previously said that it is looking at a power range of around 40,000lb-thrust for the MoM.

The airframer is currently seeking proposals from engine manufacturers for the MoM, says Kelly.

“I’m pretty confident there will be two engine [options] on the next generation Boeing,” says Udvar-Hazy on the self-coined 797. He adds that he expects there will be one option from General Electric and another from aPratt & Whitneyand Rolls-Royce consortium.

MARKET MAKER OR DUD?

The major US airlines, as Kelly points out, cannot drive the MoM programme alone. The aircraft would have to attract orders from carriers around the world to succeed, which raises questions about the larger market for a small twin-engined jet liner.

In July 2016, Boeing forecast a total market of 4,000 to 5,000 aircraft for a MoM-sized airplane but noted that the Airbus A321neo and A330neo would take a portion of this, leaving a demand for roughly 2,000 to 3,000 units.

“There’ll be a growing need for an aircraft in that category,” says Udvar-Hazy. “It’s not magnified today but if you look at the lifecycle of that airplane, there will be a need.”

Asked about Airbus' long-range variant of the A321neo, Levy says it "does a nice job but it doesn’t quite meet all the needs we have out ofNewark".

Airbus, while agreeing that Boeing needs a clean-sheet aircraft in the middle-of-the-market segment, thinks a twin-aisle aircraft is the wrong idea.

“Light [twin-aisles] will never compete with a good single-aisle stretched airplane,” says John Leahy, chief operating officer for customers at the European airframer, at ISTAT. “Aerodynamically and physically, the widebody will just have more weight and more drag for the loads that you're carrying.”

He points to the Airbus A310 and the 767-200 as examples of small twin-aisles that never met expectations.

At least one fleet manager at a major airline scoffs at Leahy’s comments, saying that a clean-sheet twin-aisle with today’s composite and engine technology could certainly achieve the economics of a narrowbody.

“There’s a lot of medium-sized aircraft demand, you’ve just got to get the economics right,” they say.