[Gorduz]

Sounds plausible to me. EM waves can just as waterwaves reflect as a result of atmospheric conditions (ala themal layers in the water). If one made a system thats able to analyze a wave sent upwards, then reflected downwards to hit the plane. Then reflected upwards and downwards to the radar again it should be no problem to detect a stealth plane. Now the problem is how to seperate that wave form all the others, but in theory it should be possible.