It's amazing to me that the ET/UFO cranks would take the publication of these patents at face value.
As others have posited, likely another explanation is warranted: 1) luring foreign militaries down blind alley's of expensive research, 2) putting out these patents to only later debunk them and thereby possibly muddying the waters for some legitimate revelations, 3) a simple prank, etc. etc.
Is it possible to verify that the filer is legitimately the U.S. Navy, or could anyone just file a patent and list the Navy as the assignee?