The Harrier vertical take-off fighter-bomber appears to be on its way to being another of those warplanes that will serve for half a century. The Harrier was developed jointly by U.S. and British firms, and first entered service in 1969. That version was used mainly by the British Royal Navy and the U.S. Marine Corps. It was a 11 ton aircraft (7 tons when taking off vertically) that carried about two tons of weapons. In the 1980s, a more powerful 14 ton version was developed, which could carry three tons of weapons.
On the downside, the Harrier has the highest accident rate of any jet fighter. This is largely because of its vertical flight capabilities, which give it an accident rate similar to that of helicopters. In the last twenty years, India has lost half of its 30 Harrier vertical takeoff fighters to accidents, and the fifteen remaining aircraft often cannot fly because of a shortage of spares. The U.S. Marine Corps has lost a third of its 397 Harriers to such accidents in 33 years. Over 800 Harriers have been built. They will be replaced by over 600 F-35Bs by the end of the next decade.
The British Royal Navy's two carriers were built to carry sixteen Harrier GR9 aircraft each. Normally they carry eight, but because of the reduction of the Harrier force (two dozen older Sea Harriers were retired in 2006), and merging Royal Air Force and Royal Navy Harriers into a joint task force, plus the demand for Harriers in Afghanistan, and aircraft sidelined for maintenance and upgrades, there developed a shortage. Thus one British carrier recently put to sea with only four Harriers. The Royal Navy is building two new 65,000 ton carriers, to replace the three current 21,000 ton carriers (one of them inactive and in reserve). Britain is buying American F-35B vertical takeoff aircraft, and the new carriers will carry 24 F-35Bs each. But these aircraft, and the new carriers, won't be in service for another 6-8 years. So the Harrier shortage will be a problem for a while.
The F-35B, which will replace the Harrier, is a 27 ton aircraft that can carry six tons of weapons and is stealthy. In vertical takeoff mode, the F-35B will carry about twice the weapons as the Harrier, and have about twice the range (800 kilometers). But that is then, the Harrier is now, and probably will still be in service by the time the 50 year mark (2019) rolls around.