N21466 Wow...weirdest looking airplane ever? Make that 2 of the weirdest looking aircraft ever, together in one shot. The Convair has a 707 nose attached for experimental purposes (more of N21466)
N979UA 21544/523 is in fact a 291A originally operated by Frontier mk1, and part of a half a dozen 732s batch later sold to United Air Lines (more of N979UA)