I have no idea how to evaluate this. Does the use of a special delivery stamp and a special delivery mark on the back make this more interesting to collectors? I have no idea how to price it for resale. Any hints appreciated.
Interest to a SD collector? Yes. Interest to non-SD collectors of Zepp flight items? Not so much. It is a Nickels and that carries some interest to some and less to others. I wonder if the card he made with SD stamps arrived back any faster than any of his other cards and letters on the flight.
The biggest interest would normally be the SD on a postal card. Yet the Zepp up-rating overwhelms the SD alone.
So if you add to the price for the SD, you will be waiting longer for an interested buyer willing to pay the added price.
These flight covers and cards were a philatelic free for all and most any stamp can be found on them including special delivery, special handling (no purpose) and all 12 values of parcel post, all except the 75 cent late usages. The 75 was still selling in DC. just months prior to the flight.
By now the real question is what did you price it at, did it sell and for what price?
The rate for cards from Lakehurst to Lakehurst was $1.76 so the card was over franked to start. It is also perhaps the most common leg of that flight and as a card it is less desirable than a cover. Also, it has a detraction and that is that it is cancelled in New York City. Also, first flight cover collectors tend to prefer flight covers and cards that are franked with airmail stamps. This one does not have any airmail stamps on it - just definitives. The flight was not from NYC, but rather it began in Lakehurst, New Jersey. The more desirable Lakehurst dispatches on this flight are the ones that were actually cancelled at Lakehurst, NJ rather than at other cities where the Zeppelin never went. As for the Special Delivery, as was stated above it did not really mean anything in terms of the flight since all of the mail on the flight went on the same Zeppelin and traveled together. It did get special treatment once it returned to the US and was forwarded to the sender in Washington, but for most all first flight collectors that is not something that matters since their are interested in the flight itself and not how it was handled or the final destination of the collector who prepared it after the flight was over. Cards and covers from this flight, either posted in Los Angeles or Lakehurst tend to sell regularly in the range of $30 to $50 on Ebay, though there are some dealers who have so called "auctions" where they have silly starting bids in the hundreds - of course those do not get bids unless they catch someone who does not know the market for these.