If your plane is German (with the maltese cross), and you have originated from the northeast airport (or east carrier), and you see a zeppelin, you are on the team that shoots the zeppelin.
That's at least what I've seen. But then again, since these games are a glitch, you never know! I generally quit out of glitch games. One of the early indications that it's a glitch is if I originate from a carrier, it's not Dogfight with all reds, and I have no bomb. And it says shoot zepp, but sometimes it doesn't. Lack of bomb flying from a carrier makes me go "Huh?" Then I double check the mission on the player board, but that might make me go "Huh?" again. Then I go to camera view to check my insignia, or note what carrier I came from, and if I don't quit, I go after the zepp if I'm German.
Confused? Me too. That's why I generally quit those.
Zup has seen the posts.
Manfred