I am researching a book about Attu Island during WWII. How would I go about getting permission to visit the old airbase there? How would I charter a boat to the island?
Alexai Point Army Airfield is the airfield used in World War 2. The Airfield is abandoned and can be visited without permission having closed in 1946.
Further west, he naval airfield that became "Naval Air Facility Attu" is also closed but can be used for emergencies, however I suspect that you are more interested in Alexai Point