I'm going to say here what worked for me to get the second card. firstly in zeppelin you have to pack a punch in a weapon and with the weapon with pack a punch shoot in valves where a jet of gas is coming out, when you press the zappelin button the valve where the jet of gas is coming out does a noise, you have to shoot the valves with a pack a punch gun 5 times in 5 valves. when you leave zappelin on the left of the map in relation to spawn there will be a card on top of a barrel. at least it worked for me.

* if I commented something that is wrong please tell me what I said wrong so I can correct it.*