bombers were downed. In May 1941, RAF night fighters shot down 38 German bombers. By the end of May, Kesselring's Luftflotte 2 had been withdrawn, leaving Hugo Sperrle's Luftflotte 3 as a token force to maintain the illusion of strategic bombing. Hitler now had his sights set on attacking the USSR with Operation Barbarossa, and the Blitz came to an end. Aftermath Luftwaffe losses Between 20 June 1940, when the first German air operations began over Britain, and 31 March 1941, OKL recorded the loss of 2,265 aircraft over the British Isles, a quarter of them fighters and one-third bombers. At least 3,363 Luftwaffe aircrew were killed, 2,641 missing and 2,117 wounded. Total losses could have been as high as 600 bombers, just 1.5 percent of the sorties flown. A significant number of the aircraft not shot down after the resort to night bombing were wrecked during landings or crashed in bad weather. Effectiveness of bombing The military effectiveness of bombing varied. The Luftwaffe dropped around of bombs during the Blitz, which disrupted production and transport, reduced food supplies, and shook British morale. The bombing also helped to support the U-boat blockade by sinking some of shipping and damaging more. Despite the bombing, British production rose steadily throughout this period, although there were significant falls during April 1941, probably influenced by the departure of workers for Easter Holidays, according to the British official history. The official history volume British War Production (Postan, 1952) noted that the greatest effect on output of warlike stores was on the supply of components and dispersal of production rather than complete equipment. In aircraft production, the British were denied the opportunity to reach the planned target of 2,500 aircraft in a month, arguably the greatest achievement of the bombing, as it forced the dispersal of the industry, at first because of damage to aircraft factories and then by a policy of precautionary dispersal. In April 1941, when the targets were British ports, rifle production fell by 25 percent, filled-shell production by 4.6 percent and in small-arms production 4.5 percent. The strategic impact on industrial cities was varied; most took from 10 to 15 days to recover from heavy raids, although Belfast and Liverpool took longer. The attacks against Birmingham took war industries some three months to recover fully. The exhausted population took three weeks to overcome the effects of an attack. The air offensive against