In war movies:
Close air support isn’t a magic solution. It can be very difficult for the pilot to discern friend from foe, too.
Which leads to the saying “Close air support and friendly fire ought to be easier to tell apart”. 
Staying on war, in this case pre-Gun/Artillery type, with swords and stuff, it is almost always shown as two groups of swordsmen running at each other in a disorganized crowd and pairing off for a series of mano-a-mano fights.
They did have Generals back then, folks, and they did try to run battles with a little more organization than that. Fighting (ala Braveheart, to name one), only gets you in a position where you can’t support each other and leaves your sides and back vunerable. There were reasons that the phalanx/tercio was the primary battle formation for thousands of years…
Maxim 5.