you can do almost anything in you LDs if you have the concentration and imagination, but you have to know in your subconsious and consious mind what it would be like... you cant know what something feels like if you have never experienced it. Obviously most impossible things you have tried in your dreams have worked, but those things you have some idea how they would come about, or what they would look/feel like ect... but flying in mid air with no aid of anything else is something your mind has no knowledge about (or hardly any), so the nearest thing to actually doing it would be to think in depth about it, or go swimming (which is a similar concept to flying)! the swimming idea is a really good one because it's the nearest thing you have experienced to flying. sorry i rambled!!!!!!