ALAMEDA, Calif. » Historians and aviation enthusiasts commemorated this week the 75th anniversary of the first commercial flight across the Pacific Ocean.

The China Clipper seaplane took off on Nov. 22, 1935, from San Francisco. (Honolulu was on the route.)

Fifty-nine hours and four stops later, the Pan American Airways aircraft landed in Manila, carrying 1,800 pounds of mail — a delivery that would have taken 15 to 16 days by steamship.

The Alameda Naval Air Museum re-enacted Monday radio broadcasts for the flight’s bon voyage, which drew more than 25,000 spectators to Alameda at the time. San Francisco International Airport also is hosting an exhibit on the famed China Clipper, and the Alameda post office provided a special postmark for its mail.

"It was an audacious gamble and a great leap forward," said John Hill, an assistant director at SFO and curator of the exhibit there. "Every airplane that crosses the ocean even now is flying in the wake of the China Clipper."

The four-engine Martin M-130 narrowly got off the ground. The aircraft was so heavily loaded that Capt. Edwin Musick could not clear the San Francisco-Oakland Bay Bridge, which was still under construction.

With thousands watching, Musick flew under the span’s cables — dodging some construction material — then gained altitude over the Golden Gate. The plane had overnight stops in Honolulu, Midway Island, Wake Island and Guam before reaching its final destination.

The successful voyage sparked public excitement over the China Clipper, inspiring postage stamps, toys, souvenirs, a beer brand and a Hollywood film starring Pat O’Brien and Humphrey Bogart. Musick also made the cover of Time magazine.

"This event occurred right in the heart of the Great Depression," said Ed Schneider, of the Alameda museum, who directed Monday’s radio re-enactment based on the old transcripts. "To watch this big silver seaplane lift itself out of the bay and fly off to these exotic places must have been a thrill."

A year later Pan Am began offering passenger service on its trans-Pacific planes, and it was not until 1939 that the airline would offer commercial service across the Atlantic.

The Martin seaplanes were later replaced with the Boeing B319, which could carry more passengers, and aviation advances eventually ended the era of flying boats after World War II.