83 ) First Flight Issue - stamped envelopes experimental / helicopter / 20's up

Description

83 ) First Flight  Issue - stamped envelopes experimental / helicopter / 12) 1920's / 28) 1930's /  10) 1940's /  4) 1950's  /  25) 1960's /  4) 1970's - few foreign  - some duplicates - a few  age spots - yellowing ---- most  very clean - will ship bulk in priority mail envelope  - as is no returns -use your knowledge & photos  to bid -  photos take precedence over written mistakes  - - no combined shipping on this