United Airlines continues to evaluate adding a 100-seat aircraft to its mainline fleet, less than a year after it cited the aircraft category's poor economics for the conversion of its Boeing 737-700 order to larger variants.

"There does seem to be an opportunity and fit for an aircraft with around 100 seats to fill that gap in our network, but on the other hand the problems with the complexity cost for a new fleet type is a big concern," said Howard Attarian, senior vice-president of flight operations at the Chicago-based carrier, in a letter to employees on 18 August.

There is a 42-seat gap between United's largest regional aircraft, the 76-seat Embraer 175, and its smallest mainline narrowbody, the 118-seat 737-700.

That gap is smaller at both American Airlines and Delta Air Lines, both of which have 100 seaters in their mainline fleets. American has 20 Embraer 190s with 99 seats, though it will retire the type in 2019, and Delta has 91 Boeing 717-200s with 110 seats. Both carriers have 76-seat regional jets in their feeder fleets.

"It’s our responsibility to look at every option and thoughtfully weigh all of the associated factors before we arrive at any decision, and that’s what we’re doing as part of our ongoing fleet plan analysis," says Attarian on the evaluation of a 100-seat aircraft at United.

A spokesman for the airline affirm's his comments, saying it is always looking at ways to "fly more efficiently and make the best use of our fleet".

United upgauged and deferred all of the 65 737-700s it had on order in November 2016, converting them to four 737-800s and 61 737 Max. It cited a preference for the latest technology and desire for more seats to defray unit costs for the decision.

The carrier continues to send mixed messages about the possibility for a 100-seat mainline aircraft. In January, United president Scott Kirby told employees that the economics of such an aircraft "just don't work" for the airline due to higher operating costs.

However, prior to Kirby's joining the company in August 2016, airline executives maintained that there was a need for a small mainline aircraft, a fact that prompted the 737-700 order in early 2016.

“There is a natural need for a small mainline narrowbody,” said Gerry Laderman, treasurer of United and then acting chief financial officer, in November 2015.

The airline, whose 100-seat aircraft evaluation dates back to at least 2014, was considering both the Bombardier CSeries and Embraer E2 family before it placed the 737 order.

Delta has been the most successful at adding a 100-seat aircraft to its fleet. It used the addition of the 717 in 2013 as a carrot to pilots in exchange for more large regional jets in its feeder fleet.

The Atlanta-based carrier will continue this upgauge strategy with the up to 125 CS100s that it ordered in April 2016.

United has a similar clause in its pilots agreement. If it adds a new small mainline narrowbody, including either the CS100 or E190-E2, it can add up to 70 more 76-seat regional jets to its feeder fleet.

The carrier has engaged in a similar fleet upgauge cascade as Delta. It has shifting 50-seat regional jet flying to 76-seat aircraft, large regional jet routes to Airbus A319s and 737s and on upwards to its small fleet of domestic Boeing 777-200s.

United will continue this upgauge strategy when it begins taking 737 Max 10 in 2020. Attarian says in the letter that the majority of these aircraft will replace 737-800s and -900ERs in domestic markets.

Source: Cirium Dashboard