The character, Robert H. Goddard, asks a couple of times about building a rocket. Presumably this is more than a nod to the American engineer/physicist Robert H. Goddard who in 1926 launched the first liquid fuelled rocket. He is often regarded as the man who enabled space flight. He was ultimately responsible for over 200 patents, among which were designs for multiple stage rockets and liquid fuel propulsion.
There is a reference to the apparatus having a "Fessenden timer". This seems to be a reference to Canadian inventor Reginald Fessenden (1866- 1932), best known for his work on sonar and radio.
Robert H. Goddard (1882-1945) was a sickly child who fell behind his classmates. He graduated from high school in 1904 (around the time this episode is set). He received a B.S. in Physics in 1909, an M.A. in Physics in 1910, and a Ph.D in Physics in 1911. He received 131 of his 214 patents after his death.
Whitcomb L. Judson (1846-1909) invented the Judson fastener, called a "clasp-locker," in 1890. The first application was for shoes, to relieve the tedium of fastening the tall shoes which were fashionable. In 1923, B.F. Goodrich used them on a new design of galoshes called "Zippers," and the name of the rubber boot transferred to become the name of the device itself; in 1925, zippers started being used for clothing.
In the promotional video for the F.L.A.S.H. an animated globe is seen plotting the proposed route for the tunnel. It is made by iMovie (software for editing movies at home on an Apple Mac) and well beyond the graphic capabilities of the time.