Two book recommendations:

"Splash of Colors" by John Nance -- the definitive history of BN's decline and bankruptcy. Published circa 1985. Nance was a BN pilot at the time; this was his first book; he's now a major aviation author and ABC News aviation analyst.

"A Life in Advertising" by Mary Wells. Her agency, Wells Rich Greene, did the Braniff "If You've Got It, Flaunt It" campaign and painted the planes up so they were nicknamed the "jellybean fleet" ... and she eventually married Harding Lawrence. Lots in the book about Braniff flamboyance.