Aerophilately is the branch of philately that specializes in the study of airmail.
Philatelists have observed the development of mail transport by air from its beginning, and all aspects of airmail service have been extensively studied and documented by specialists.
Astrophilately, the study of mail in space, is a related area.
International Federation of Aerophilatelic Societies (FISA) is the umbrella organization for aerophilately though aerophilatelists have formed a number of organizations around the world; many of them put out a variety of specialized publications.
Federation Internationale de Philatelie (FIP) also maintains a commission.