The contents of a Supply Crate are random, based on the list below. A Supply Crate is the loot container dropped by the aircraft which appears every 1, 3, or 7 Days (if Air Drops are enabled). There is a limit to the number of unopened drop crates that can exist in the world at once, so when you hit that limit, air drops will stop until. Yes, they will stay there until you find them, but they will stop putting up orange smoke after a set amount of time OR until you enter the same map chunk as it. It used to be in hours, but now is in days, so it will drop at 12:01 pm when the drop days hits. What time they drop used to depend on what you had the frequency timer set at.