My first thought was did he know Hillary.
I suspect severe icing at flight level followed by rapid loss of altitude. Weather conditions in the area were not very good, strong front moving through, but just my hunch, could have been structural failure from turbulence. According to news reports the plane had reached a height several thousand feet above regional hilltops (but probably in the worst of the weather).
Hillary or Obamao.
The known Alberta connection is Cruz. Ted Cruz’s parents became Canadian citizens and were living in Alberta, registered to vote in Calgary.