Board Thread:Manga/@comment-7278867-20170901020814/@comment-1327106-20170901035421

Probably because it wouldn't have been effective. Marley has roughly WW1-era tech and the Germans tried this in WW1. Zeppelins could cross the ocean, but they're also at the whims of the weather. A good breeze going the wrong way meant that the zeppelin would probably not make its destination. (Hopefully it could make it back home.)  There were zeppelins that went on bombing runs, dropped their payload at what they hoped was London, and actually missed the city by miles.

We don't know the distance between Paradis and Marley, but it's probably similar to the English Channel, which means that the issues the Germans had would likely be experienced by Marley.

If they got a few over there it would be a way to make themselves known and destroy some things, but if you're trying to discretely recover the Founding Titan without  potentially  s etting a whole bunch of Wall Titans loose it's probably not the way to go. I doubt the bombing would be that effective against normal Titans either, since there's not much aiming involved. Too many chances to not actually kill any.