Developed under DARPA's Hummingbird Vertical Take-Off and Landing (VTOL) Unmanned Aerial Vehicle (UAV) program, the Boeing A160T is currently in production for DARPA testing and for the US Special Operations Command. The original piston engine powered Hummingbird flew for the first time in 2002. Currently 11 A160Ts are in production at Boeing for DARPA. The latest version, A160T (Turbine Hummingbird) offers dramatic improvement in endurance and performance over the baseline vehicle. It is designed for autonomous operations at a range of 2,250 nautical miles and mission endurance extending more than 20 hours. Its cruising speed is 140 knots and operational ceiling is 25,000 to 30,000 ft. The aircraft will be able to hover at an altitude of up to 15,000 ft.

Key to the Hummingbird's endurance and station-keeping performance is the proprietary optimum speed rotor technology, designed to improve the engine's efficiency by adjusting the rotation speed of the rotor according to the changing flight conditions, such as altitudes, gross weight and cruise speed. Operational A160Ts will be capable of persistent intelligence, surveillance and reconnaissance; target acquisition; direct action; communication relay and precision re-supply missions.
In October 2007, A160T completed a 12 hour test flight carrying a 500 pound payload at an altitude of 5,000 feet simulating multi-sensor operational mission. The flight used less than 60 percent of the aircraft's maximum fuel, demonstrating the advantages of the A160's design, including its unique optimum speed rotor. The 12-hour flight followed an eight-hour flight on Sept. 27 during which the Hummingbird carried a 1,000-pound payload module. Ultimately, Boeing plans to fly the aircraft for 18 consecutive hours with a 300-pound payload. At AUSA Boeing displayed a model of an armed version of the A160T, loaded with an EO payload and eight Hellfire type missiles. The vehicle has a length of 35 feet and a 36-foot rotor diameter.
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