You saw the title.
Main idea is to make radios actually have use instead of attracting hungry zomboids to your local bungalow. Airdrops would be a random event and could be a civilian aid airdrop, or a military aid airdrop. These would be announced over radio. This is a good idea because it would actually make radios and walkie talkies (such as the military HAM radio and the military walkie talkie) actually useful. This would make players keep a walkie talky on them at all times (on the belt) in the chance there's an airdrop called in somewhere to grab. You could also create some kind of zed story at these locations as well such as : Airdrop was taken before you could get there : military was ambushed by bandits at the airdrop : civilians went to the airdrop was ambushed by bandits or military, vice versa. This would be gold in multiplayer as gangs of players would compete for the airdrop in the chance of getting their group more powerful fire power.