who else thinks dragon mounted combat possibly against another dragon hundreds (hopefully thousands) of ft. in the air would be difficult.

Very carefuly.....

Not if you know how to dogfight a dragon... My question is this: how are we supposed to collect the loot from their fallen bodies?

to Oblivion with the loot!, just imagine the Glory of a dragon falling from the Sky after you slew it and his soul being absorbed by the Dragonborn mounted in his trusty Dragon shouting DOVAHKIIIIN!! just like the dragonborn did in the Skyrim pre-release foottage (Divines Beth should have kept that epic shouting when absorbing a dragonsoul!)