 It operated as 40-Mile Air (in reference to the Fortymile River) from 1970 to 1989, when it was split into two companies by Marvin's sons Charlie and Art.The base in Fairbanks, Alaska operated by Art Warbelow then assumed the name Warbelow's Air Ventures, Inc..The base in Tok, Alaska continued to operate under the 40-Mile Air, Ltd. name.