Flight_helmet utility alias

BUR #18812 has been rejected.

create alias pilot_helmet -> flight_helmet
create implication flight_helmet -> helmet

Wikipedia said
A flight helmet, sometimes referred to as a "bone dome" or "foam dome", is a special type of helmet primarily worn by (military) aircrew.

A distinct type of helmet. It is not just designed for pilots, also aircraft crew in general.

What's the tag for race helmets? I see several posts under pilot helmet of racecar-type helmets, like post #4805674. There's also a bunch of mecha pilot helmets in pilot_helmet (bodysuit or mecha), not sure if those would qualify as flight helmets.

This bulk update request is pending automatic rejection in 5 days.

This bulk update request has been rejected because it was not approved within 45 days.

The bulk update request #18812 (forum #249601) has been rejected by @DanbooruBot.