Timothy Paradox

I was standing by the edge of a large river, one which ran through a city in Germany. The year was some time in the early 1900's, maybe the 20's? Early 30's? Commercial aviation wasn't a thing yet. Large crowds were gathered by the river to watch a massive air show, where the government and companies showed off experimental aircraft. Many of there were quite large (some craft were single-seaters, I think? Jets?), and were designed to take off from the river. One of the craft taking off was huge, had a strange shape, and had 6, perhaps even 8 propeller engines. It also had the German Cross on the tail (the Iron Cross, not a Swastika). I looked to my left, and saw my grandmother (on father's side). She was German and has been dead since '09. I remember thinking none of the people believed mass commercial air travel was feasible. Being from next century, I of course knew better. I thought these demonstrations had to change their minds.