We have also seen these WWII Revetments (I've also seen the term
"parking circles" which is a bit more intuitive) at many airfields in
Alaska. At many the circle was surrounded by a high berm which served
both to hide the planes and to protect them from aerial strafing. They
were also often located in an irregular rather than a linear pattern for
the same reason. These are still visible along the currently-used runway
at the Kodiak airport and (in the trees) at Yakutat, among others.

Catherine Williams
Northern Land Use Research