Not too many details...
But I am pretty sure this is referring to the previously mentioned
California Aero Mfg. & Supply Co. of Cleve Thomas Shaffer and Roy C. Scott, especially as aircraft
and balloons are mentioned and the city of San Francisco.
Shaffer has been secretary of the Pacific Aero Club, was an active balloonist, had built gliders and in 1909 one of the very first biplanes in the Western United States.
http://www.genealogy.com/forum/surna.../shaffer/3479/
http://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=SFC19090810.2.9#
If Shaffer in 1909 already had a company, I can't say. He might have constructed his first devices with the help of his sister Geneve Shaffer in an own or rented workshop and the inauguration of a company might have taken place in 1910, as the Oregon Evenig Herald indicates.
Also I have seen that company named "Shaffer Aero Manufacturing Co.", "California Aeronautic Mfg. & Supply Co." as well as "California Aeroplane Manufacturing and Supply Co."
There even is an aircraft of that company that has survived until today - the Blériot-type monoplane with 40 hp Elbridge Aero Special inline engine built for John W. Hamilton in 1911, now displayed at the Canada Aviation and Space Museum in Ottawa.
http://casmuseum.techno-science.ca/e...bleriot-xi.php
Just as told before, this company was dissolved in 1911 and the employees Meyeroffer and Thompson kept up the business for just another year under the name of California Aviation Co.
May I ask what you are after ?
Aquilius