airmail

This term describes the expedited transport of correspondence via aircraft, carrying a connotation of urgency and international reach. It is typically used in administrative or logistical contexts to distinguish between surface mail and faster aerial delivery. As a noun, the word is uncountable when referring to the system of transport or the collective mail being sent. It does not take a plural form in these contexts, requiring phrases like "a piece of airmail" if a specific item must be singled out.