1937 China Clipper Airmail Cover First Flight to Macao, Addressed to Michigan

Airmail cover flown on the historic April 21, 1937 China Clipper flight from San Francisco to Macao. Features the official blue cachet for the first transpacific leg to Macao, San Francisco postmark, and clear Macao backstamp. Addressed to Birmingham, Michigan and franked with 50 and 20 U. S. airmail stamps. Very clean example with typed address and bold markings.