There are about two dozen stamps or sets that make everyone's short list of favorite stamps and for most US collectors this list is headed by the 1930 Graf Zeppelin set. Air travel technology has been static in our time. The commercial jet airliner first entered service in the 1950's and since then the technology has been tweaked but not changed. In the early days of airmail, though, it wasn't clear whether airplanes or dirigibles would win the competition to be the carrier of choice. Certainly airplanes were faster, often by 150 miles per hour or more. But before 1930, airplane travel was dodgy. Planes were small and unreliable and crashes were frequent. Dirigibles were slower but more reliable, could carry far more mail, and were considered safer. (This issue was finally settled in favor of planes after the Hindenburg crash in 1937.) The 1930 Zeppelin set was issued for a special series of flights from the United States to Europe on the airship Graf Zeppelin (Count Zepppelin was a German count who was involved in the early development of lighter than air travel). The 65c value paid the one way postcard rate from the US to Germany. The $1.30 paid the one way letter rate or the round trip postcard rate and the $2.60 paid the round trip letter rate. From the first the Zeppelin stamps were collector favorites and the high face value in the first year of the Great Depression (a face value equivalent to over $50 in today's money) limited the quantities sold. From the start the Graf Zeppelin set has been a philatelic favorite and many US collector believe they have crossed the threshold from moderate to serious collector when they acquire this set.