The range difference between (say) a P51D and a Mk9 spitfire was mostly the amount of fuel that they could carry....
P51 D - 180 USG (wing/main) + 85 USG (rear fuse) + 220 USG (drops) = 485 USG =
404 imp Gallons
Spitfire Mk9 - 96gal (main) +75 gal (rear fuse) + 45gal (drop) = 216 imp gallons
Guess which aircraft had the longer range
