An aircraft left out in the elements will not last several hundred years like an arrowhead. The Navy has received quite of bit of flak for its stance on USN aircraft wrecks. They emphasize preservation and minimize recovery by outside parties. Some have accused them of hoarding the sites for their own museum. While their stance may be a bit too harsh or unfair, it does have some merit.
Most people are under the impression that the wrecks are sitting there for the taking.
On public land there are laws that protect the wrecks and the Navy has been the only one to bring it to our attention. Aircraft crash sites provide information, history, and education. Aviation archaeology's goal is to preserve the information and history and to ensure the education of the public about the aircraft and the history surrounding them. If you like visiting these sites, please help preserve them so that other people can also see them. While we are at it, let's try to record the sites while they are still around and we can still interview some of the participants.