I liked braineaters point of not believing in possibilties in real life and thus having troubles with them in dream. what I also think is that even though more things are possible in dreams, I doubt it is possible to have complete control over them in much the same way you don't have complete control in real life - it is the unaccounted-for that makes life interesting anyway.
dreaming and waking may or may not be very different from each other - both are states in which something seems to be going on.
I think that dreaming doesn't solely take place in the head, as our cultural assumption seems to be. with that in mind I don't think that it is neither possible nor desirable to have full control. but yeah, learning to fly shouldn't be too much of a trouble
keep trying