Flying taxis could whisk passengers across Paris or help with emergency medical care from December, operators said on Thursday, while acknowledging that the dream of showing off the scheme during the Paris Olympics was impossible.
The joint venture between Paris airport operator ADP and German start-up Volocopter is aiming for a passenger flight "by the end of the year" from a platform floating on the river Seine, they said.
Initially, ADP and Volocopter wanted to trial passenger flights from the river over the summer, taking advantage of the global attention paid to the Olympic Games.
But there has been a "delay of a few weeks" in official certification for their Volocity flying machine from the European Aviation Safety Agency, ADP executive director Edward Arkwright said.
This was because of "small vibrations" affecting the craft's engine, which is manufactured by a US supplier, ADP chief executive Augustin de Romanet told Franceinfo broadcaster on Thursday.
"We retain the hope of flying these machines over the Seine before the reopening of Notre Dame (Cathedral)", he said.
Notre Dame is scheduled to reopen its doors in December, more than five years after suffering a devastating fire.
In the meantime, the joint venture is organising flight demonstrations with a passengerless prototype.
A first took place on Thursday at the Saint-Cyr-l'Ecole aerodrome west of Paris, with two flights on a short circuit above the site, at an altitude of around 30 metres (100 feet).
Another is scheduled for Sunday in the grounds of the Palace of Versailles, from the spot where the first flying machine in history, the Montgolfier brothers' hot air balloon, rose into the sky in 1783.
In its current version, the two-seater aircraft designed by Volocopter is equipped with 18 battery-powered rotors arranged in a crown above the cockpit and is much quieter than a helicopter.
The transport ministry and ADP -- which is 50.6-percent state-owned -- have in recent months stressed the Volocity's potential for medical evacuations or organ transport, rather than talking about "flying taxis", which is associated with a mode of transport for the rich.
This switch in tone comes after the project met with hostility from Paris city officials from both sides of the political divide.
City hall has criticised the project as an "ecological aberration".
It has issued a court challenge to a recent decree published by the transport ministry authorising the creation of a helipad for the machines.
France's highest administrative authority ruled in July against city hall, pending a decision on the merits of the case, expected in the autumn.
The decree says the platform's operating permit runs until December 31 "at the latest".
