The status of ground units is saved, even over server restarts. So you can continue to clear an airbase/FARP even after a restart. Or if you managed to take out a radar in a SAM site, it will still be gone after a restart.
This allows players to perform recon sorties before embarking on a strike mission, to find out what kind of defenses are at a target for example.
Log into SRS and Discord, make your presence known and ask if you need help!