C13 VF example tied by Washington DC machine cancel, cachet of C.L. Elliott at UL, blue handstamp of Zeppelin & clouds and ms "First Day Cover" beneath, not flown, faint flap marks, o/w XF (Planty C13-2 $1,750, Scott CV for flown cover w/o FD cachet) (Image)

Cat. $1,000 SE

C13 (2) June, 1930 flights, one Lakehurst to Friedrichshafen flight on postal card, one Lakehurst to Seville flight on Zeppelin PPC, both w/ purple diamond map cachet, first w/ additional round red cachet, VF (Image)

Cat. $320 SE

C14 1930 Lakehurst to Friedrichshafen flight w/ purple diamond map & red round flight cachets, May 31 NY cancel, June 6 receiving cancel on back, stamp w/ CCr LR; F-VF (Image)

Cat. $375 SE

C15 on May, 1930 round trip flight w/ purple map & pink flight cachets, w/ 17¢ Wilson #622 paying registry fee but marked "not in registered mail", collector's notes in pink at left, otherwise F-VF (Image)

Cat. $575 SE

Group (12) diff Century of Progress covers franked w/ C18, incl cachets of Anderson, Ioor & Linprint; diff routes, other stamps added, one Akron-Germany to Sweden on Fair stationery; gen F-VF+ (Image)

Est. $500-600 LE