I'm not sure thats true.
Watch some documentaries, where in numerous ones they state that spitfires, hurri's etc were partly manufactured on american equipment shipped in, and individual plane components were as well.
i'm pretty sure it's not true. it seems kinda funny, that 50-60 years aftert the fact, that new information ""surfaces"" stating that britain was never in trouble.
c'mon. outnumbered, but not outclassed, in london, the civilians needed to go underground, everything was rationed, you had supplies comming from all over the world, including the usa, and were losing pilots almost faster than new ones could be trained. one of those links mentioned a day that all RAF fighters were airborn.
although it was after the BOB, i also don';t think germany would've fallen without the constant 24/7 airraids, which england could not have sustained without the help of the mighty 8th air force.
i have however wondered why usa went for daytime raids and uk went for night time.....i had heard in the past that it had to do with the lancs being not well enough protected?