OK... Here's one that I find to be a head-scratcher. Perhaps Kyle and the other pennant guys will find it to be a mystery as well.
Check out this green Brooklyn Pennant with the Bum inside of Ebbets Field. Classic Trench design... right?
Well, not so fast!
Check out the second photo. We have the classic blue felt Trench "Bum in Ebbets Field" Pennant (complete with Trench Logo). But also note the infamous "Creepy Uncle" Bums Pennant from Ad Flag. The font stating "Da Bums" (right above his head) is identical to that on the green Trench Pennant.
So is it possible that Trench and Ad Flag shared some of the design work, or that some pennant artists of the era worked for both companies? Perhaps someone here has a better explanation.