I wondered whether an assassin would get on a plane that was going to have an accident. Shooting Brown before takeoff solves that problem, but leads to further questions.
Placed on the plane after shooting? Seems unlikely. Shot while seated? Plausible.
Someone seated next to him? Maybe it wasn’t going to be occupied.
Plane hit mountain while landing, IIRC. If so, a long time to hope nobody bothered the VIP.
Assassin left plane after shooting? This was before 9.11, so plausible.
Carlos Ghigliotti, FLIR expert investigating Waco, suicide.
Kathleen Willey’s cat.