McPhetridge met Herbert von Thaden, who was a former United States Army Signal Corps pilot and engineer who worked on developing the first American all-metal aircraft, the Thaden T-2.
The Thaden T-2 was a 1920s American four-seat all-metal cabin monoplane built by the Thaden Metal Aircraft Company of San Francisco, California.
The Thaden T-4 Argonaut was a 1930s American four-seat all-metal cabin monoplane built by the Thaden Metal Aircraft Company of San Francisco, California.