Hawker Siddeley Harrier to the pilot by a head-up display and a moving map display. The Harrier's VTOL abilities allowed it to be deployed from very small prepared clearings or helipads as well as normal airfields. It was believed that, in a high-intensity conflict, air bases would be vulnerable and likely to be quickly knocked out. The capability to scatter Harrier squadrons to dozens of small "alert pads" on the front lines was highly prized by military strategists and the USMC procured the aircraft because of this ability. Hawker Siddeley noted that STOL operation provided additional benefits over VTOL operation, saving fuel and
Harrier Jump Jet of the upgraded "Sea Harrier FA2"; this version entered operational service on 2 April 1993. The Sea Harrier was also procured by the Indian Navy, the first Indian Sea Harriers were entered squadron service during December 1983. As early as 1973, Hawker Siddeley and American aviation manufacturer McDonnell Douglas were jointly working on development of a more capable version of the Harrier. Early efforts concentrated on the development of an improved Pegasus engine, designated the "Pegasus 15", which was being tested by Bristol Siddeley. During August 1981, the program received a boost when British Aerospace (BAe) and McDonnell Douglas signed