Tango-Bravo, with reference to your question, "On what routes were Braniff's 707-138Bs typically flown while in service?"
I don't have any specific references to answer your question, but as a kid who hung around Dallas Love Field in the 60s and 70s, I remember the 707s (in general) were used on the long-haul routes to major markets such as JFK
, Kansas City (MKC
at that time) and Minneapolis (I think prior to de-regulation Braniff was the only airline providing service between DAL
--some nonstop, some via MKC
, and the 727s and BAC-111s made LOTS of stops between DAL
) as well as short-haul, high-density markets such as Houston, Texas and San Antonio. As I remember, some of the San Antonio flights continued to Mexico City and/or Acapulco.
Sorry, nothing concrete, just some good (maybe not very accurate) old memories of the deployment of Braniff aircraft.