This United States event cover commemorates the International Civil Aeronautics Conference held on December 12, 13, and 14, 1928. It features a striking cachet printed directly on the stamps, highlighting the aviation theme with an airplane flying over the U.S. Capitol and the Washington Monument. The cachet is integral to the stamps themselves, which are issued specifically for this important international aeronautics event.

The cover bears a 2-cent red stamp and four 5-cent blue stamps, all dedicated to the International Civil Aeronautics Conference. The stamps display the dates of the conference and the event's title prominently. The postmark is from Miami, Florida, dated April 26 at 2 PM, and includes the location "Fla." The reverse side shows a Cristobal, Canal Zone receiving postmark dated April 27, 1930. The typed address is to Dr. Edwin P. Meiners at 6600 Delmar Blvd., St. Louis, Missouri. The cover was routed via Miami to Cristobal as noted by the typed routing instruction "Via Miami-Cristobal."

This event cover is a valuable piece for collectors interested in early aviation philately and international aeronautical history. The use of multiple stamps and clear postmarks enhances its appeal, making it a notable item for those specializing in U.S. event covers, aviation memorabilia, or postal history from the late 1920s.