As a general category, Event Covers commemorate an event. Most of these Flight Covers commemorate either Lindbergh's air mail routes or the trans-Atlantic flight from New York to Paris in 1927.  

One cover with ink stamp of Spirit of St. Louis and “Special Flight Lindbergh Day” has manuscript pencil note at top “Good Will & Dedication Cover.”  These have many different postmarks: Chicago, IL; Springfield; St. Louis; Peoria; South Milwaukee, WI.

Several have some version of a horseshoe with “Lindbergh Again Flies the Air Mail.” Chicago to St. Louis, Feb. 20-21, 1929. This was followed in short order with a May 20-21, 1929 group of covers celebrating the Second Anniversary of Lindbergh’s transatlantic flight.

One has a stamped cachet for the 50th anniversary 1927-1977 (Lindbergh had died in 1974, but the celebrations continued).

Several FDC’s commemorate new air mail routes, such as several Central and South American destinations (Panama, Puerto Rico, Mali, St. Lucia, Havana. Virgin Islands, Leeward Islands, Trinidad to Spain, Canal Zone, Venezuela)

Variety of notes (parts of cachet) also appear:  “’LINDY’ carried this letter from ME to YOU.’

Set of 5 Golden Jubilee/Anniversary covers with color cachets and pamphlet describing the trans-Atlantic flight.

One cover celebrates the Spirit of St. Louis and is signed by Donald Hall, the designer of the airplane.