On the first piece of mail ever delivered:
The first bits of mail were delivered among the first balloon flights ever made — in the U.S., the first quasi-official piece of airmail was a letter from president George Washington that went aloft in the first balloon flight (1793) in this country, deliverable to whomever it was that first came to greet the balloon in wherever it landed. The first semi-regular delivery of mail in the U.S. was again by balloon, beginning in 1859, which still precedes the first sustained use of explosives dropped from aerial vehicles by five decades.
I recently signed up for some aerial lessons of my own, and adore the idea of writing a letter to both no one in particular and the first person to greet one upon landing. Noted.