Traditionally, helicopters were used by the military for evacuating wounded soldiers or carrying weapons and supplies from one place to another. However, during the Vietnam War, helicopters were reinvented as an offensive weapon.

Although the military use of helicopters started during World War II, it was still in its initial steps of development. For instance, England and Russia used autogiros for observation duties, Germany used the Flettner FL 282 Kolibri for limited combat at the Mediterranean Sea, and the US Coast Guard used the Sikorsky YH-4A for dropping practice bombs against submarines.

Military helicopters were first used extensively during the Korean War, mostly for cargo delivery roles. The US Army started testing Bell 47 OH-13, Sikorsky S-51 H-19 and Piasecki H-21 helicopters fitted with machine-gun pods and rockets. The true revolution in military helicopters came with the Vietnam War, wherein the US Army demand for a new gunship helicopter equipped with the newly designed turbo shaft engines resulted in the invention of the Bell 207 Sioux Scout.

The Vietnam War also gave rise to the development of a new form of warfare known as air mobility, as helicopters enabled armies to be lifted deep into enemy territory, striking suddenly and powerfully.

Modern inventions have added more maneuverability for military helicopters and have also changed the design, outlook durability and safety of the machines. The most revolutionary change in helicopter engineering is the use of the NOTAR, or no tail rotar, design that blows air through a long slot along the tail boom, to produce forces to counter the torque.

Nowadays, most modern armies have formed new air combat units using choppers armed with anti-tank missiles, and helicopters have became a vital piece of military hardware in the inventory of the world 's powerful armies.