flight attendant hat
A type of hat worn by female flight attendants. It generally has a round shape, fold-over flap all around the sides with rounded crown that's usually also dome-shaped.
The flap around the sides usually slopes toward the front where it is parted. However, there can be flight attendant hats without such feature (Danbooru post #7256364). The crown can also sometimes be indented (Danbooru post #6836856) or otherwise round but not dome-shaped.
It should be noted that this tag does not apply to other hats also worn by flight attendants like garrison cap or pillbox hat. Garrison cap can look similar but flight attendant hat usually has rounded, dome-like crown while garrison cap has creased or hollowed crown and a general triangular shape when viewed from the front.