You have several options.
You can have Air Units, Assets and no FAC. In this case your air units attack only using assets (determine the turn and target point before the game starts).
You can have Air Units, no Assets and a FAC. In this case your air units attack only after the FAC has a target in LOS(or gets a target from a recce unit via recce action) AND manages a successfull command roll. Note the Errata on bombers and FACs.
You can have Air Units, Assets and a FAC. In this case your air units attack using both methods above.
If your army list says "2x Aircraft Ground Attack", it means for EACH aircraft unit you have you can have maximum of two assets. So to answer your question: yes, you can recycle.
Let's you have 1 aircraft unit, a FAC and 2 assets. Your aircraft unit attacks twice on turns and targets you decided before the games started and your FAC could try to give them orders to attak more during other turns.
Sorry if that was too 101
iA