Uh...Having done so more reading on the Ho229 there were none captured intact by the US and what was rebuild was never flown for fear of the unreliability of the Jumo 004. Much of the documentation of the Ho229 was destroyed too, so rather than bothering with it it seems the US just mothballed their one example and forgot about it. They let the Hortons go after several interviews and pretty much left the German research alone and kept on with their own work, which did not have the feature mentioned above. Any info about the Horton work was either not provided to or ignored by Northrop. As to the advantages of the flying wing, most air forces were quite conservative and just didn't want to run the risk of an untried radical new design given budget cuts after the war; what funding they did have was plowed into conventional designs. It was only much later when stealth technology was revived that the wing got a second look. If anything no one wanted to take any risks until the stealth benefit was really known and of course by then funding was ridiculous for the air force thanks to Reagan. That and finally getting the Korean and Vietnam wars out of the way, which sucked up most funding that crippled the more radical aircraft projects like the Flying Wing.
http://greyfalcon.us/The Horten Ho 229.htm
Interesting site to use as reference.