The Moller M400 Skycar is a flying car that promised to let you take off from your backyard and fly to your destination at 350 mph. Paul Moller won’t give up on his 50-year, $150 million quest to make his vision for a flying car a reality.

The M400 Skycar was developed over many years and first flown in 2001 at the company’s shareholder meeting. It has since flown (under a restricted environment) many times. This vehicle was featured on the covers of Popular Science, Popular Mechanics, and the topic of countless news articles and broadcasts including 60 Minutes, ABC, Bloomberg, CNN, and Discovery Channel.

In July 2017, Moller International listed the 2001 M400 prototype on eBay at the starting bid of $1 million. The more impatient bidder could have used the Buy It Now option for $5 million. The listing attracted no bidders. The M400 was relisted, this time with an opening bid of $250,000.

A collector who buys the M400 will receive it in its original 2001 flight form and condition, complete with eight Rotapower engines that produced over 720 hp allowing the M400 Skycar to take off and land vertically. It should be noted, however, in this original form, it does not have FAA approval and a condition of this offer is that it cannot be flown. Nonetheless, this vehicle can be the centerpiece of any car or aircraft collection in a public or private museum.

The Moller 200X, the invention of Paul Moller, a former professor of aerodynamics and engineering, is built of graphite, carries computers, and eight lightweight Wankel engines. The proof of concept 200X is a flat, round 10 foot wide saucer, which can hover out of ground effect.

First flown in February 1989, the machine, which flew more than 150 times, is to make way for the production version, the Merlin.