What happens in a plane crash?
Last Day on Earth: Survival Guide
There may be instances during your exploration where you'll get a notification that a plane has crashed nearby. On the world map, a message will appear telling you to check if out if there's anything useful that may have survived.
Plane crashes will show you a site that you can run or walk to. These areas have a number of monsters as well, but they will contain a lot of crates, etc. that have different kinds of items. Be mindful of your energy though since a crash site is only available for a limited time period, and you need to be able to get there on time. Be sure that you have the inventory space available in order for you to gather the amount of items that you want. Also, Plane Crashes can attract other players so be prepared to fight or run away when needed.
The items that you can get here vary from different items for crafting, as well as to special items in order for you to unlock new places such as passes. If you do not have the inventory space, you can swap items on the crates that you find as well.