Moving Air and Ground units with the same speed?

One thing i noticed yesterday. I wanted to protect my bot squadron against bombers with some fighters.
Sadly, the Fighters were way faster than my bots...so they were alone at the front and got shot by Anti Air...and for exactly that i had grenadiers.

So now i was wondering...i know that formations are not there, and that units move as one huge ball.
But is it somehow possible (maybe even through a clientside mod) to let Air units who are grouped with ground units move at the same speed? Same for speed difference between units, like bots > tanks.
Or is that atleast planned? I have no problem with micro management, its just...well...annoying^^

Why not just do assist

That...might work