pilot jacket

So called because it was worn by seamen: pilots (helmsmen) and pilots (assistants to helmsmen).

pilot jacket (plural pilot jackets)

1. A pea coat.
   • 1912, Arthur Conan Doyle, The Lost World […], London; New York, N.Y.: Hodder and Stoughton, →OCLC:

     The door was opened by an odd, swarthy, dried-up person of uncertain age, with a dark pilot jacket and brown leather gaiters.

• pilot-jacketed