Heart Aerospace, on the airport at Gothenburg Airport in southern Sweden, wants to bring inexpensive, four-motor electric flight to the masses. With $35 million (29.4 million euros) in recently acquired backing, the small team at Heart is working toward making a 19-passenger, four-motor airliner a reality. Their ES-19 is a single-aisle design with eight-rows of single seats and three-seat row at the cabin’s rear. Those 19 seats are a selling point, with United Airlines signing purchase contracts for 100 of the $ 9 million machines. Mesa Airlines follows suit for another 100 and Finnair, Finland’s national airline, has expressed interest in another 20. Funding from Bill Gates’ Breakthrough Energy Ventures and other investors totals over $35 million. For a niche market, the possibilities are expansive, with many small airlines flying short routes ready for such a craft. Heart sees the 19-seat market as promising, since few 19-seat commuter liners exist anymore. Part of that is economic, with small turboprops being …