Taranis, named after the Celtic god of thunder, is easily BAE Systems' spookiest-looking aircraft.
Sleek, with swept-back wings, the grey, wedge-shaped Unmanned Combat Air Vehicle (UCAV), or drone, is "the most advanced aircraft ever produced in the UK," says the firm.
Taranis is designed to be the prototype for a combat drone - capable of carrying out long-range strikes in hostile territory.
With the UK's latest jet fighter, the Typhoon, scheduled to need a replacement by 2030, the success of this project will help the Royal Air Force make decisions on the future numbers of manned and unmanned combat aircraft.
Taranis's exact details are secret, but it is roughly the size of the RAF's current jet trainer, the Hawk - the plane used by the Red Arrows display team.
Hide the engine Designed to have a low radar and infrared signature, it has a complex exhaust system to minimise any tell-tale heat trail from its engines, making it hard to detect or shoot down.
"What we had to do was fully embed and hide the gas turbine in the body of the aircraft," says Conrad Banks, Rolls-Royce's chief engineer for research and development - Rolls-Royce being one of the firms working with BAE on Taranis.
At this week's Farnborough Airshow, BAE was keen to highlight the news from the latest flight tests at "an undisclosed location" where Taranis demonstrated its advanced stealth capabilities.
"The Taranis project is a tremendous example of how the UK government and industry can work together," says BAE's Chris Garside, engineering director of future combat systems.
Just don't ask what kind of weapons such a drone might carry. "That is a classified topic area," comes the short response.
Franco-British collaboration Taranis is not Europe's only combat drone in development. Just across the Channel France's Dassault Aviation is testing a similar aircraft, called Neuron.
Neither will see active service - both are designed to flight-test technologies for use in future drones.At Farnborough, France and the UK announced a two-year £120m ($205m) study on a potential Future Combat Air System, which would combine the lessons learnt from Taranis and Neuron.
Such European collaboration is badly needed, say some industry insiders, if Europe is ever to produce its own combat drones on an economic basis, rather than rely on off-the-shelf models from Israel or the United States, which currently dominate the market.
Last year, even France opted to buy US Reaper drones as a money-saving measure.
Individually, Europe's nations are too small to be an effective market for combat drones. Only if they can develop a multinational drone would such a system be economical.