In a surprise move, Porsche recently announced it's joining forces with Boeing to develop a flying car concept. Porsche isn't the only mainstream automaker that wants to take to the skies, however, as Audi was also developing a production version of the Pop.Up.Next concept that debuted at the 2018 Geneva Motor Show with Airbus. We say "was," because the project has failed to take off. According to Auto News Europe, the project has been suspended and Audi's partnership with Airbus is being reviewed.

While a test flight with a scaled-down model was successful last year, making a working full-size prototype presented many challenges for Audi. "We believe it will be a very long time before an air taxi can be serially produced that does not require passengers to change vehicles. In the modular concept of Pop.Up, we were working on a solution with the highest complexity," Audi said in a statement.

The concept presented at the 2018 Geneva Motor show featured a flying passenger capsule that sits on top of a car chassis. It was designed to pick up a customer from home and drive them to a heliport, where the car connects with the flight module.

The flight module featured four pods, which each had eight helicopter blades. A 26-hp electric motor powered each blade, giving the Pop.Up.Next a combined output of 214 hp. Flying speed was capped at 74 mph. With its 70-kWh battery pack, the flight module could only travel 31 miles before requiring a 15-minute recharge.

While the Pop.Up.Next will no longer be entering production, there are plenty of other automakers that want to take to the skies. Uber wants to trial a flying taxi service and Aston Martin unveiled the Volante Vision Concept at the Farnborough Airshow in England, a "luxury concept aircraft" capable of taking off and landing vertically like a helicopter.