B-29 fleets attack Axis oil in 1941

What if all Allied four-engine bombers became B-29s in 1941, with matching production facilities?

Romanian oil becomes an immediate target, while the new bombing threat drives airfield expansion, faster fighter development, and possible disruption of Barbarossa.

The scenario converts Allied four-engine bombers and their production facilities into B-29s, putting Romanian oil high on the immediate target list. Airfields are an initial objection, but the scenario is then allowed to include suitable runways alongside its explicitly transformed factories. High-altitude bombing would put pressure on German fighter development and encourage heavy fighters and earlier jet development. Those pressures would also affect Allied fighter design and the style of fighter combat. Since the question supplies only a year, the scenario is placed on 1 January 1941, before the United States enters the war or Germany invades the Soviet Union. Britain therefore receives the bombers while the United States initially does not. The resulting attacks on fuel supplies could delay Barbarossa and force Germany to reconsider its strategy.