Almost all slots are controlled by our Slotblocking System (SSB), wich controls what slots are avalible and not. To unlock slots at an airbase or FARP, the airbase/FARP first need to be captured then the slot will unlock.
Scattered around the map, there are a few slots that can only be unlocked by completing certain ”strike missions”. Locate those slots and finish the assigned objective and they will be unlocked.
Log into SRS and Discord, make your presence known and ask if you need help!