Here it is, the only helicopter that only operated by United States Army, the Bell OH-58 Kiowa while in flight. Nearly 500 OH-58s operated by the Army, one of the largest fleet helicopter in the world and one of the longest lifetime' operation, the Bell Oh-58 has been operated by the Army since 1969 until present.
The Kiowa is single-rotor, single-engine military helicopter, manufactured by Bell. The main purpose of this rotorcraft are observation, utility as well as direct firing support. The OH-58 built based on Bell 206 Jet Ranger helicopter.