The Wright borthers' innovation was less in the airframe of their planes than in the way they powered them... gliders were already fairly widely known at the time so the basic fixed-wing lift principles were already in place. It was the engine and propellor system that was finally settled on that was a first, and the Wright brothers came up with that entirely on their own. It has been argued that a frenchman actually achieved powered flight first, but he did it independently and only beat the Wrights by a year at most (at the time, news wouldn't even travel that fast either).
And actually it's "Flying Wing" or "Lift Body" IIRC. The B2 is hardly the first (though it's the first to be true stealth). And yes, the allies did use a lot of captured weapons research in the years following World War II, that is widely known and hardly suprising. The Germans had the ingenuity to come up with the designs, but by the time the war was nearing its conclusion they did not have the infastructure to devote to making untested designs. And besides, that's how war works. The Soviets took an American B-something (I want to say it was a B-29) and reverse-engineered it just after WWII, and put it on the production line as an "Original Soviet Design" despite the fact that they had barely changed the paint job from the original model.
A lot of those designs are pretty cool, I must say. Not Freespacy, but cool.