The C-97 Stratofreighter was an air freighter service in the 1950s. The aircraft was based off of the B-29 Super Fortress bomber. Boeing made a civilian version called the 377. The struts were easily identifiable as coming from the 1950s. The tires were made at Goodyear and the wheels were manufactured by Rantoul Engineering. The oxygen tanks were a generic kind that are still being used on aircraft. 
- Vixen 03, an USAF plane that went missing in 1954.
In the book, the C-97 is called a Stratocruiser, which is what the civilian Boeing 377 is called.
- A detailed article on C-97 Stratofreighter on Wikipedia
- A detailed article on the Boeing 377 from Wikipedia