Some of the earliest airmail deliveries in the US were made over fairs and carnivals (as in, bags of mail were dropped at fairs and carnivals). Why is this? I don’t know. Maybe it’s a simple combination of airplanes being curious attractions in the early 1900s and carnivals and fairs being events that brought out a lot of people. According to this document:
The Department’s purpose in developing airmail service was in part “to demonstrate to men of means” that
commercial aviation was “a possibility.”
Certainly, fairs and carnivals would be good places to conduct such demonstrations.