aviation cap; flying helmet
A protective or uniform cap worn by pilots or aircrew, often with ear flaps and a chin strap.
パイロットは飛行帽をかぶってコックピットに座った。
The pilot put on an aviation cap and sat in the cockpit.
Compound of 飛行 (hikō, 'aviation, flight') and 帽 (bō, 'cap, hat').