United States
usa-19880000-b-001
page = 1
Click here for higher resolution image
Width: 238 mm
Height: 104 mm
Location: Box 1004
Stamp ID = 7225
Can find no informataion on the Milwaukee Flyers. Dated the envelope by the first day of issue of the stamp because there is no cancel.
From Linn's "Stamp Issuing Entities Of The World" page.
United States of America (1847-)
Stamp-issuing status: active; Population: 248,709,873 (1990). Republic occupying the central portion of North America, along with Alaska, Hawaii and a large number of island possessions in the Caribbean Sea and the Pacific Ocean.