The whole Harrier story rests on a single idea — Michel Wibault’s thrust-vectoring concept, turned into a practical engine by Rolls-Royce’s Stanley Hooker as the Pegasus. Nine evaluation aircraft, the Kestrel FGA.1, were flown by a tripartite squadron of British, American and West German pilots in 1965. When the supersonic P.1154 was axed the same year, the subsonic Harrier survived, first flying in 1966 and entering RAF service with No. 1 Squadron at Wittering in 1969.

No other Western vertical-take-off combat jet ever reached front-line squadrons. The Harrier did — and stayed there, in one form or another, for more than four decades.

Rival V/STOL designs bolted separate lift engines into the fuselage — dead weight in cruise. The Pegasus instead split its whole thrust across four swivelling nozzles rotated in unison, so the same engine that flew the aircraft also lifted it. That single decision kept the Harrier light enough to be a useful combat jet rather than a hovering curiosity, and it is why the layout survived unchanged from the 1960s P.1127 to the F402-powered AV-8B.

The Sea Harrier was slower than the Mirages and Daggers it faced in 1982, and slower is usually fatal in a dogfight. VIFFing changed the maths: by swivelling the nozzles in forward flight the pilot could dump speed almost instantly, forcing a fast attacker to overshoot and become the target. Combined with the all-aspect AIM-9L Sidewinder and aggressive flying, it turned the Harrier’s biggest weakness — a lack of raw speed — into a close-combat advantage.

Production totals depend on where you draw the line. The first-generation Harrier / Sea Harrier / AV-8A line is commonly cited at around 700 airframes (MilitaryFactory quotes 718 for the early line). Add the second-generation Harrier II / AV-8B and RAF GR5/7/9, and the whole family runs to over 800. Firm unit-cost figures are unreliable: they span multiple variants, decades and currencies, so treat any single dollar figure as approximate. What is certain is the aircraft’s value — it gave small carriers and forward strips a fast jet that nothing else could match.