If you subscribed to Popular Mechanics as a kid in the 1950s or 1960s you were pretty sure that by, say, 1978 the skyways would be jam-packed with flying cars.
And even that seemed way behind schedule. In 1940, Henry Ford said: "Mark my word: A combination airplane and motorcar is coming."
He may yet be proved right.
Last week, Germany's Volocopter received $30 million in funding to develop an electric flying taxi, with Daimler among the firms chipping in.
Volocopter is developing a five-seat vertical takeoff and landing aircraft aimed at the taxi market and plans to carry out initial demonstrations in the fourth quarter of this year.
And Volocopter is not alone. Potential competitors include German startups Lilium Jet and eVolo, as well as U.S.-based Terrafugia and Joby Aviation. Commercial aircraft and helicopter manufacturer Airbus is also developing a single-seat "flying car" with auto design company Italdesign.
Meanwhile, the ride-hailing giants are waiting impatiently.
Uber says it wants to offer a flying-taxi service within 10 years.