The trial flight of a new hypersonic plane which could have eventually led to 60 minute flights from London to New York failed miserably after the experimental 'Waverider' jet broke apart over the Pacific Ocean.
The US military had hoped the Boeing X-51A would fly at its top speed of 4,500mph (more than five times the speed of sound) for five minutes before cutting its engines and falling into the sea.
However the WaveRider flew for only 31 seconds before breaking apart and plummeting into the Pacific Ocean north-west of Los Angeles, reported Reuters.
Although the plane took off under the wing of a B52 bomber as planned, the problem with the fin meant that the plane could not use its 'scramjet', a unique hydrogen engine which allows the jet to achieve hypersonic speeds by 'pulling' the air needed to burn its fuel from the air around the plane.
A 'faulty control fin' was blamed for the failure of the test, identified 16 seconds after a rocket booster was fired to help the jet accelerate.
"It is unfortunate that a problem with this subsystem caused a termination before we could light the scramjet engine," Charlie Brink, of the Air Force Research Laboratory at the Wright-Patterson Air Force Base in Ohio, said in a statement.
"All our data showed we had created the right conditions for engine ignition and we were very hopeful to meet our test objectives."
The plane is built by Pratt & Whiney Rocketdyne and is co-funded by Nasa and the US military. There have only been four X-51A jets built for the military and this marks the third failure of one of the hypersonic jets. The Pentagon and Nasa were hoping to use the project to develop faster missiles.
It has not been decided whether or not the Air Force will go ahead with a fourth test, reports the BBC.