Zeppelin
There never was a Zeppelin service to India.  Hence, Zeppelin and Catapult flown mail to and from India (hereinafter referred to as Indian Zeppelin Mail) is relatively uncommon. This subject is also quite neglected by Indian philatelists, with not a single publication dedicated to the subject of Indian Zeppelin Mail.. However, I have tried to put together a collection of such items. It has been an incredibly fascinating journey for me in reading up and researching the postal rates, routes and postmarks of such mail.
I appeal to fellow philatelists to contribute to this study by sharing more images and insights by using the Contact Us link provided on this web-site.
WARNING
Beware of this seller on ebay.
He lists Zeppelin material he does not possess at bargain prices. 
Seller name: Stampsworl-52