C6, 530 tied by Stockton CA Dec 10 1924 duplex cancels on air mail cover to Switzerland, BS San Francisco Ded 10, but no receiving cancel (Image)

Est. 50

1929, Graf Zeppelin Round the Worlld flight, violet flight cachet on cover franked with C10 & C11, cancelled Los Angeles Ag 25, 1929, BS Lakehurst Aug 29, 1929 (Image)

Est. 40

1930, Interrupted flight, AAMS 300921, Chicago to Newark, plane struck a telephone pole while attempting an emergency landing, partially burned cover with h/s (Image)

Est. 50

1933, Nation Air Races, Los Angeles, three covers to San Jose, pmk July 1, 3 & 4, all with purple cachets, also 1932 Army Review, Los Angeles, Jul 28, purple cachet, addr to Melbourne, Australia, (Image)

Est. 35

1933, Graf Zeppelin 1st flight, Miami, FL to Humboldt Park Station, Chicago, IL, cachet of Century of Progress Expo at left, on cover franked w/C18, 50¢ green (Image)

Est. 40

1933, Graf Zeppelin, 1st Flight, Chicago, IL to Friedrichshafen, Germany, addr to San Francisco, Ca, cachet of Century of Progress Expo at left on airmail cover, franked w/C18, 50¢ green, light ink marks at left (Image)

Est. 40

1933, Graf Zeppelin, Akron-Fredrichshapen - 1st Flight Chicago, IL to Akron, OH, addr to Chicago, IL, cachet of Century of Progress Expo at left on cover, franked w/C18, 50¢ green (Image)

Est. 40

1934, Air Mail Special Delivery cover from Columbus, Ohio, to Hamilton, Ontario, Canada, franked with 16¢ blue CE1, three different RMS cancels on reverse, also 2-line "Received without content at Hamilton, Canada", backflap never sealed, strange!! as cover originated from The Supreme Court of Ohio (Image)

Est. 30

1936, Hindenburg flight from Lakehurst, NJ, May 11, to Frankfurt on Main, Germany, BS 16 May, then returned to Chicago, clean cover franked with 15¢ Liberty & 25¢ Airmail stamps (Image)

Est. 40

1936 Hindenburg flight from Lakehurst, NJ to Europe, oversized cover franked with six+ 778 souvenir sheets tied by New York May 9, 1936 first day of issue cancels, backstamped Frankfurt 14.5.36 (Image)

Est. 50

1972, Apollo 16, multicolored astronauts & logo cachet , printed illus data card enclosed, cancelled Kennedy Space Center Apr 16 1972, addr (Image)

Est. 20