Vintage US WWI Leather Aviator Flying Cap or Motorcycle Soft Helmet Fur Lined

Description

Up for sale is a
Vintage US WWI Leather Aviator Flying Cap or Motorcycle Soft Helmet Fur Lined.  I am not sure but think this is an aviator's flying cap from WWI.  I am not sure what material was used for the lining, but it looks like sheepskin wool around the bottom, brim and flaps.
The approximate measurements are shown in the photos.
Approximately 7" in diameter x 5" deep or 8" to edge of fur trim.
This is in good condition for age.  The back and side leather is worn.  There are 3 holes or slits on the brim, maybe where an insignia pin was attached.  The inside cloth lining looks good with no holes or rips. The fur lining is also worn, especially on one ear flap.
I am not an expert or dealer, only try to describe item to the best of my ability.  Please see photos and email with any questions.
F4T3