The carrier made firm orders for 50 19-seat Era aircraft from France's Aura Aero, 50 30-seat ES-30s from Sweden's Heart Aerospace, and 32 9-seat aircraft from U.S.-based Electra.

If all options are included, JSX could buy up to 150 aicraft from Aura Aero, 100 aircraft from Heart Aerospace and 82 aircraft from Electra.

The companies did not disclose the value of the deal.

Started in 2016 by JetBlue Airways founding executive Alex Wilcox, JSX operates "semi-private" flights where customers book individual seats and fly in and out of private terminals.

The order is a key endorsement for fixed-wing electric passenger planes in the world's busiest regional market, with JSX stating that the new aircraft will lower carbon emissions and operating costs while expanding flight options at over 2,000 U.S. airports.

However, analysts have said challenges remain over weight and power of batteries.

JSX plans to accept its first hybrid-electric aircraft in 2028. It currently operates 48 Embraer E145 family aircraft.

Electra and Heart Aerospace expect their electric planes to enter commercial service in 2028, while Aura Aero said its plane will enter service before 2030.

While JSX investors include JetBlue and United Airlines , the business model has come under fire from critics who advocated stricter regulations for high-volume charter flights.

(Reporting by Valerie Insinna in Washington; Editing by David Gregorio)