Well, a dragon with a jet pack is a curious idea at the beginning, but when we see the context - another age, long time before Divine Divinty, with spaceship, great weapons and powerful civilisations - that's not so "strange". The hero is a Dragon Knight, so he knows about human technology...and so can use it cleverly.
May be it's also a pretext to make the dragon mode easier to play, with the very big maps. Imagine you have to cross all the map just with your two wings... aw aw aw... "The Raven crashed, too late Sir. Uuups."
