Embraer has logged LOIs for more than 250 of its planned new turboprop, the manufacturer said Tuesday at the Farnborough Airshow.

Embraer has not yet formally launched the program—that decision is expected early 2023, with an engine choice being made by the end of this year—and is still considering whether to launch the 70- or  90-seat version of the rear-mounted engine design first.

Whichever is the first model, it is scheduled to appear in 2028, with the second following a year later.

“We have a huge number of turboprop LOIs being signed up, well above 250,” Embraer Commercial Aviation president and CEO Arjan Meijer said. The total does not include any lessors, he added. “These are actual airlines that want to operate the aircraft.”

LOIs have come in from virtually every continent, Meijer said.

“It’s a very diverse mix, in terms of operators—a combination of network carriers, point-to-point carriers and single turboprop operators,” he said.

Meanwhile, Embraer also used the show to announce that Norwegian regional airline Widerøe is the first to join the manufacturer’s Energia Advisory Group, which is studying a range of emission-free aircraft to appear in the 2030s.

Widerøe, which has committed to be one of the first airlines in the world to be emission free, will work with with Embraer to define and establish the real-world requirements for sustainable, emission free, and commercially viable aviation.

The companies will collaborate to define requirements such as infrastructure, ground handling, aircraft performance and cargo space. The Energia Advisory Group will help accelerate time to market and ultimately inform the choice of which Energia concept will come to market first.

Embraer also announced that Canadian regional carrier Porter Airlines has ordered an additional 20 E195-E2s, to add to the 30 it already has on order. The new order is worth approximately $1.6 billion at list prices. Porter retains a further 50 options.

Toronto-based Porter is the North American launch customer for the E195-E2, with the first aircraft scheduled for delivery later this year. It intends to use the latest order to extend its route network throughout North America.

Additionally, Alaska Air Group announced an order for eight additional E175 regional jets, plus options for 13 more, to be operated by its wholly owned subsidiary Horizon Air. The list price value of the contract, including options, is $1.1 billion.

The aircraft, in a 76-seat configuration (12 first class, 12 premium and 52 in the main cabin), will be delivered in Alaska livery over four years from Q2 2023.

Horizon Air announced earlier this year that it would transition to an all-E175 fleet. The carrier currently flies a mix of 31 Bombardier Q400 turboprops and 30 E175s. It will take delivery of nine E175s over the next year as part of a previous order.