Late war Zeppelins had straight crosses. I presume that the change came in at the same time as for aircraft. I should be interested to know what colours you choose for your Zeppelins. The Navy specified warship grey for all their airships but their is no evidence that any of the early ones were grey and painting the hull would have reduced the lifting capacity significantly. Navis have changed the top of their L53 class from buff to grey in recent production but the Gott Straffe England books say that a blue-flecked cloth (denim?) was used on the late war height climbers. One of the pilots who shot one of them down got above the airship and his report says that the upper hull was silver but light grey would be a good compromise between theory and practice. You can see some of my airship collection on www.coastlinesmodels.co.uk in the balloons and airships section.
: I have a P-class yet to finish, I got some
: decals on E-bay. I believe they were for
: 1/72 aircraft.
: They weren't hard to find.