Germany's Volocopter promised its electric-powered, two-seater aircraft, the VoloCity, would be ferrying passengers around the city.
While missing that deadline was embarrassing, behind the scenes a more serious issue was playing out - Volocopter was urgently trying to raise fresh investment to keep the firm going.
Now hopes are pinned on China's Geely, which is in talks to take an 85% stake in Volocopter in return for $95m of funding, according to a Bloomberg report. The deal could mean that any future manufacturing would be moved to China.
Volocopter is one of dozens of companies around the world developing an electric vertical take-off and landing (EVTOL) aircraft.
However, faced with the massive cost of getting such novel aircraft approved by regulators and then building up manufacturing capabilities, some investors are bailing out.
The concept proved attractive, with the company claiming to have orders and memoranda of understanding for 780 jets from around the world.