At 16:11, the crew departed William P. Hobby Airport as Braniff Flight 352, a Lockheed L-188A Electra four-engine turboprop, en route to Dallas Love Field. After about 25 minutes into the flight, while cruising at FL200 (about 20,000 feet above mean sea level), the aircraft approached an area of severe thunderstorm activity. The crew requested to descend to 15,000 feet and deviate to the west. Air Traffic Control (ATC) informed the crew that other flights in the area were deviating to the east and suggested they also deviate east, but the Electra crew insisted that the west seemed OK to them on their onboard weather radar: "Three fifty two does it look good (better). On our scope here it looks like to the uh a little just a little bit to the west would do us real fine."