The Hughes 369HS flown by Hagman's character was destroyed in a collision with an aerial cableway on 17th April 1982. Sadly, three of the four people on board were killed: one was the aircraft's owner, Glenn Miller (who appears in the film as the truck driver Pocatello Pete). It is unknown whether the accident occurred during filming.
Sam's helicopter is a Hughes 500C, thousands of which were built for the US Army for use as scout ships during the Vietnam War. The two helicopters of the bad guys are Aerospatiale Alouette II's, and later an Aerospatiale Gazelle (the same as used in the 1983 film Blue Thunder). The helicopter used during the aborted pickup scene is a Bell JetRanger.