IMO its rather impractical to have a flying turret, unless its just an turret that hovers just above the ground via antigrav tech. like the ones from the Halo series.
My quote:
'Meh, I don't really care anymore about the new games direction, with many loads of hours(make that years actually) on Tib Sun, YR, Generals, CnC3, and RA3, plus all the mods they come with, another game with the same old formula is rather redundant IMO. '
Hm. Good point there.
Well, I think the idea is pretty good, and should be implemented somehow.
But anyway, back to subject, since this is apparently off topic.
Like Commander32 says, it would be sensibly impractical to have a floating turret, unless it was just for looks. Of course, if the thing was to have a special use, then it could use that technique explained earlier that causes the turret to rise up, and then only anti-air units can attack it. But then the defense might have to have a base to anchor it to the spot, so couldn't a unit just destroy the base?
How about there is a base to the defense, and when it rises off of it, enemy units can attack the base instead of the turret. Once the base is destroyed, the turret can move around for a short period of time.
That could be useful but things like fire hawks can just shoot missiles at it and then bomb your base. It's just a waste of credits.
Kane the second
One easy justification is that it is help up by a balloon. For example, Balloon Mines from MidEast Crisis 2.
Your argument proves too much, as it could apply to any permanently airborne unit, like Venoms, Commanches, Hammerheads, Kirovs, etc. Of course a unit is going to die rather quickly to its counter.