I'm also new at this game,and enjoying it immensely.It seems that during the operations phase before you start the quick battle you can left click on any squad(the ones you have already chosen)and it will show you all the units you have chosen for the battle and available reinforcements.You can then click on a squad in the left column and one in the right column to exchange them.The unit symbol for a squad that has a small airplane in the lower right corner can be exchanged for an air spotter.I haven't tried air support yet so I'm only guessing but that what it seems to be to me.Like I said I'm new at this also and it's been a lot of trial and error,and I have yet to master the basics but one piece at a time seems to be falling into place and hopefully one day I can say I know how to play this game the way the developers intended.