"A future platoon could fly into a specific location and provide direct boots-on-ground seizure of a critical location," the Defense Advanced Research Projects Agency wrote in briefing materials about the project, known as Transformer, or TX. "If they encounter overwhelming enemy forces, casualties or new orders, they can immediately extract to a new location."

DARPA, which hopes to have a prototype in four years, is looking for a four-passenger vehicle which can transform in about a minute from a Humvee-type land rover to an aircraft that can take off and land vertically like a helicopter. The vehicle should be able to drive and/or fly 250 nautical miles on a single tank of gas.