Zepp Cover Collector Here

1930 South American Flight.
Friedrichshafen to Friedrichshafen (Round Trip).
Sieger 64E II; Michel LZ 127-68Hc.

Cover franked with Scott 573 overpaying the proper rate ($3.90) for the round trip. The card also contains the purple "This Article Made the Complete Round Trip" handstamp.

Wow, I've seen some really gorgeous and amazing Graf Zeppelin flight covers in this post from the rest of you! It just goes to show that there's always something great out there to be discovered. Thanks to everyone for sharing some great covers from their collections. Here's another one from my collection to keep it going. Best to all, Murph.

When I first started in philately, approximately 7 years ago, I had no idea on what to collect. I started out with Zeppelin covers (C13, C14, C15), for reasons unknown to me. I no longer collect Zeppelin covers as my focus has changed. Will consider selling my "Zep Covers" collection at stamp shows in the future. Should have taken these to GASS back in August. Crowe certs on all of these as Genuine stamp and genuinely used.
You serious Zeppelin collectors out there can determine the routes and cancellations. Thanks for viewing!

I'll be attending the WESTPEX show at the end of this month. I will be bringing the 3 Zep covers (C13, C14, C15) shown immediately in the above post, and the 3 related 2017 Crowe Certs-(not shown) for trade/sale. Preferably, I'd like to sell these as a set. Can I get an opinion as to what price I could get for these?
Don't know if a figure around $700-$800 would be fair? Too low? Too high?
Thanks for your thoughts.

Found this cover in the back of a collection I bought. I didn't even know it was there so that was a nice surprise.

I (and probably others too) am extremely envious of that find of yours. I just received an almost complete set of American airmailnstamps, with the only missing items being the zeppelin stamps.