Hi Charlezzzzz,
Welcome to The Aerodrome.
I can't help you with your uncle, but thought I would suggest a book that you might find interesting: "
A Grandstand Seat : the American Balloon Service in World War I" by Eileen F. Lebow. It's still in print, but expensive. It's also available in a number of libraries. You may be able to find a library close to you using
WorldCat.
Steve Mc