Several companies are building unmanned flying vehicles from scratch, but autonomous aviation startup Xwing is taking a different approach by focusing on software for existing aircraft. Now, the company says it's achieved a major milestone by completing the first fully autonomous gate-to-gate demonstration of a commercial cargo flight. The breakthrough saw a remotely-piloted Cessna Grand Caravan 208B utility plane (equipped with the startup's AutoFlight software stack) leave the gate, taxi, take-off, land and return to the gate by itself. Xwing says that all traffic control interactions were done remotely from the ground. The startup believes that by retrofitting existing aircraft with its autonomous system it can get to market sooner by overcoming the regulatory and technical hurdles others face.