There's plenty happening in the world of environmentally friendly aviation, with a string of clean-burning aircraft notching up milestones in recent years, including the first flight of an electric light sport aircraft in Australia, the first electric test plane to tow a glider into the sky, and the first electric aircraft to cross the English Channel. LA's Ampaire has now put into the air what it says is the largest hybrid-propulsion plane to ever take flight, with plans to kick off commercial operations in the next couple of years.

We've seen quite a few hybrid electric aircraft concepts and prototypes over the years, including the futuristic Volta Volaré, the Terrafugia Transition flying car and a test plane from the University of Cambridge and Boeing.

But never before has a hybrid-electric aircraft of this size flown before, at least according to Ampaire. Its Ampaire 337 plane is based on the six-seat Cessna 337 Skymaster, which it retrofitted with its own electric propulsion system. That means yanking out one of the two combustion engines and putting a battery-powered electric motor in its place, with the two now working together for optimal efficiency through the air.

On Thursday, the Ampaire 337 took flight for the first time in a short jaunt at Camarillo Airport Ampaire

On Thursday, the Ampaire 337 took flight for the first time in a short jaunt at Camarillo Airport, with a test pilot and flight engineer in the cockpit. Following the first outing of this prototype, Ampaire plans to continue flight testing the plane multiple times a week from June through August and gather data about the performance of its electric propulsion systems.

The information gleaned throughout will then guide the team in building a new prototype that will be used in a pilot project exploring the potential for a commercial route in Hawaii. The company imagines eventually using its hybrid aircraft to service commercial routes for regional airlines covering short distances, and hopes to begin operations in 2021.

A video of the test flight can be seen below.

Source: Ampaire