The two sky gliders that crashed in the skiing section of the movie - when the camera pulls right back out when Bond and Elektra are climbing out of the snow - where is the wreckage?
They take quite a nasty fall from the general wreckage area in that little mini-avalanche. It's feasible that they tumbled well clear of the main wreckage.
I think you forgot that there was an avalanche. The wreckage must have been buried by the falling snow. Since the pilots are dead, they couldn't dig the snowmobiles out of the snow.