Helicopter

From WarWiki

A Helicopter is a type of aircraft used for a variety of purposes, ranging from recon and transport to offensive maneuvers. Some historians atribute the theoretical creation of the helicopter to Leonardo Da Vinci ^[1], whom drew pictures of a then fictional flying machine. Their first military use was during World War II. ^[2] afterwards they were used frequently, and became a staple of the United States Air Force during the Vietnam War.

References:

1. ↑ http://www.mos.org/leonardo/qtvr3.html
2. ↑ http://www.glue.umd.edu/~leishman/Aero/history.html