They flew into Knoxville McGhee-Tyson, too. I still find Pennsylvania Central Airlines stuff here and there (and buy it whenever I can).
In 1957, when this mailable listing of flights and costs (Knoxville to Washington DC – $28 and change) was printed, Capital was flying high with their Vickers Viscounts (eventually foreclosed on by Vickers). Hard times were soon upon the company and it was sold to United in 1961. The piece is 4 x 9″, folded.