They still play Wings on the Discovery Wings channel. The early episodes with the British narration are getting rare and the XB-70 was one of those episodes. I saw it in 1988 but not since. Here's a Googled photo of the ill-fated XB-70 just before the collision. Joe Walker's orange-tailed F-104 is on the B-70's right wing and you can see Walker getting in close to the right wing of the XB. Walker, a highly-experienced test pilot to include flights in the X-15, surely knew about wingtip vorticies (basically horizontal tornadoes that trail aft from the wingtip of every aircraft) but he may have underestimated the strength of the massive XB-70's wingtip vorticies.
