The Fieseler Fi 103, better known as the V-1 'Buzz Bomb', (German: Vergeltungswaffe 1, retaliation weapon), also colloquially known in Britain as the 'Doodlebug', was an early pulse jet-powered example of what would later be called a cruise missile. The V-1 was developed at Peenemünde Airfield by the German Luftwaffe during the Second World War. The first of the so-called Vergeltungswaffen series designed for terror bombing of London, the V-1 was fired from "ski" launch sites along the French (Pas-de-Calais) and Dutch coasts. The first V-1 was launched at London on 13 June 1944, one week after (and prompted by) the successful Allied landing in Europe. At its peak, over a hundred V-1s a day were fired at southeast England, 9,521 in total, decreasing in number as sites were overrun until October 1944, when the last V-1 site in range of Britain was overrun by Allied forces. This caused the remaining V-1s to be re-targeted on the port of Antwerp and other targets in Belgium, with 2,448 V-1s being launched. The attacks stopped when the last site was overrun on 29 March 1945. In total, the V-1 attacks caused 22,892 casualties (almost entirely civilians).

The underground V-1 storage depots at Saint-Leu-d'Esserent, Nucourt and Rilly-la-Montagne, as well as the launch sites, were bombed during Operation Crossbow.