Robert Ivan Nichols, aka Joseph Newton Chandler III, aka John Doe

Darrel Nichols missing since 1973 from Utah, but too young I think.
https://www.findthemissing.org/en/cases/7512/172

George Gregor Nikita... last name has a "nik" in it, so might be worth looking at.
https://www.findthemissing.org/en/cases/25453/7/

This guy would have been born in the early 30's so is probably the right age. Around the same height.





"George Nikita was lost in an aircraft crash over Lake Champlain in January of 1971.

The aircraft and the remains were not recovered. Last radar contact was over Lake Champlain, the plane was last seen flying over Juniper Island. Nikita was the pilot and one of five people believed to be on board the corporate jet when it disappeared in a heavy snowstorm. The plane was owned by Cousins Properties of Atlanta, Ga. Some reports indicate that the private jet was carrying $1 million or more in cash or negotiable bonds.

No oil slicks were found and the lake froze over four days later. On April 24, 1971, several pieces of airplane debris, including a tire on a rim came ashore."

Perhaps he took the cash and pulled a DB Cooper.