(AP) — United Airlines says it’s investing in a startup that hopes to build small electric-powered planes that might be flying in a few years. United made the announcement Tuesday, but didn’t say how much it’s investing in Sweden-based Heart Aerospace. United says the startup’s ES-19 “has the potential” to carry passengers short distances by the end of the decade. United says it has conditionally agreed to buy 100 of the 19-seat planes if they meet certain standards, which United isn’t spelling out. It says that Mesa Airlines, which operates many United Express flights, is making a similar pledge for 100 planes.