Mid 19th century; earliest use found in The Spirit of the Times: a chronicle of the turf, agriculture, field sports, literature and the stage. From pilot + coat.
Definition of pilot coat in US English:
pilot coat
nounˈpʌɪlət kəʊt
historical
Pea-jacket.
Origin
Mid 19th century; earliest use found in The Spirit of the Times: a chronicle of the turf, agriculture, field sports, literature and the stage. From pilot + coat.