aerogram

noun4

1. •
   A thin piece of foldable and gummed paper for writing a letter and serving as its own envelope for transit via airmail.
2. •
   (old-fashioned) A wireless message.

   • An aërogram to the Examiner yesterday from Quito announced the success of the second attempt, and details of the achievement were at once secured. — 1890
3. •
   (old-fashioned, rare) A telegram whose transmission included at least one segment sent via airplane.

   • Mr. Holt Thomas gave some details of a projected scheme of communication which combined the telephone or telegraph with the aeroplane. Messages sent by the system would be described as aerograms. — 1919
4. •
   (rare) A pneumogram.