The speed of HGVs can exceed Mach 5, or 6,000 kilometres per hour (3,730 mph). The technology is being developed or deployed by a small number of countries that includes China, Russia and the United States.

The French glider, called V-Max, was launched from a sounding rocket -- which allows precise measurements -- that went airborne in southern France late Monday, the source told AFP.

France issued a warning notice covering a corridor of around 2,000 kilometres (1,240 miles) for air and sea traffic ahead of the launch.

Local media reported that white traces in the sky were visible from the ground Monday night.

When the V-Max programme was launched in January 2019, then-defence minister Florence Parly said: "Many countries are equipping themselves with this technology. We have the know-how and we cannot wait any longer."

The French V-Max programme is being developed by Ariane Groupe, a defence company specialising in space launches and best known for Ariane rockets.

Unlike ballistic missiles whose trajectory after launch is fixed, the flight path of HGVs can change at high speed at any point during flight, allowing them to zigzag past air defences and take evasive action once targeted by anti-air missiles.