Based on the speed of the carriers they could be deployed anywhere in the World "at a moments notice".
fast strike teams of Spec Ops could use them as a base of operation.
Airborne divisions could be dropped Down from them making bridgeheads anywhere and Thus negating terrain and static defenses.
Immagine an airbourne aircraft carrier in WW II???!!
It flies in from any direction, drops troops on Berlin end of war.
Öffcourse all of this is pure fiction as you would need insane abounts of fuel to feed the beast or some alternate source of energy that doesnt weigh much.
The other HUGE problem would be hiding the damn thing from radar.
Overcome those obstacles and VIOLA - Insta terror weapon :-)