San Francisco – Oakland Seaplane Ferry
Prelinger Archives (B&W, Silent) Air Ferries Ltd
Aerial Bus Services – Flight Global March 14th 1930
Amphibious airplanes offered frequent six-minute flights between San Francisco and Oakland in 1930.
Popular Mechanics
Special Pier For Air Ferry Speeds Bay Traffic
Loening C-2 Air Yacht From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Loening_C-2
Loening Cabin Amphbian – Flight Global June 7th 1928