UPDATE:

A Cessna 421 "Golden Eagle" was the aircraft type involved in the crash last Saturday (http://en.wikipedia.org/wiki/Cessna_421). This aircraft is relatively fast and complex for a piston engine type of its age; being pressurised it can fly at higher altitudes.

On board the aircraft were a father and son:
  • Scott Clarke (41), a doctor from Springfield
  • Patrick Clarke (67), a prominent businessman from Omaha
NTSB is investigating.