Harbour Airlines, the largest seaplane airline in North America, will first convert its six-passenger DHC-2 de Havilland Beaver. It plans to test the aircraft later this year, and if all goes well, the company will convert its entire fleet. It will target flights under 1,000 miles, like it makes between its Seattle and Vancouver, Canada, hubs. According to magniX, such "middle mile" trips made up 75 percent of worldwide airline flights in 2018.

Harbour Airlines certainly isn't the only company looking to go electric. The aviation industry currently contributes 4.9 percent of global carbon emissions, and in the US, air traffic is responsible for 12 percent of carbon emissions. Earlier this year, Boeing completed the first test-flight of its autonomous electric aircraft. Uber hopes to get a hybrid-electric flying taxi off the ground around 2023, and NASA has an electric aircraft "testbed" in Ohio. We'll see who flies past the finish line first.