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
British Aerospace Harrier II service. The decision to retire was controversial as there was no immediate fixed-wing replacement in its role or fixed-wing carrier-capable aircraft left in service; in the long term the Harrier II is to be replaced by the Lockheed Martin F-35 Lightning II. Development of a much more powerful successor to the Harrier began in 1973 as a cooperative effort between McDonnell Douglas (MDD) in the US and Hawker Siddeley (in 1977, its aviation interests were nationalised to form part of British Aerospace) in the UK. First-generation Harriers were being introduced into Royal Air Force and United States Marine Corps; operational