Lot Of 3 1957 First Day Covers Air Force United Nations National Education

Lot of 3 first day covers from 1957 featuring the United Nations, National Education Association, and the 50th anniversary of the US Air Force. Good used condition, postmarked as shown. Each cover is in individual sleeves. The Air Force cover has some staining. Classic philatelic collectibles for stamp and cover enthusiasts. Great for display, research, or adding to a collection.