Bomber LeMay divided his 720 planes among three islands: Guam, Saipan and Timian. The P-51 fighter escorts were based on Iwo Jima, which is about half way to Tokyo. I suspect one reason for putting the planes on multiple islands was to minimize congestion. With four runways you could get all the planes in the air four times faster than if they were all using the same one. The trip was 1500 miles one way and took 15 hours round trip. Each B-29 could hold 9,000 gallons of fuel. 9,000 gallons times 720 planes means each bombing mission needs 6.5 million gallons of av-gas, not counting the fighters or refueling on the way home. A WW2 era oil tanker (ship) could hold about 4 million gallons.
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