noun. An airmail letter in the form of a lightweight sheet of stationery that folds into its own envelope for mailing at a low postage rate.

noun. a thin piece of foldable and gummed paper for writing a letter for transit via airmail

noun. a wireless message

noun. a letter sent by air mail

"British conceptual designer Hussein Chalayan created the "Airmail Dress" in 1999, which collapses or expands, depending on your point of view, into or out of a standard blue aerogram; the resulting breakdown between a human being and an envelope is funny, and disturbing, and rather touching."

letter  missive