ANCHORAGE, Alaska -- Families of three missing Katmai National Park employees have offered a $65,000 reward to find their plane in southwest Alaska.

The three and the pilot disappeared Aug. 21 in the de Havilland Beaver on a one-hour flight from Swikshak Lagoon in Katmai National Park to King Salmon.

Authorities said Marco Alletto, 47, of King Salmon, was flying the plane.

The passengers were park employees Mason McLeod, 26, of Jacksonville Fla., and brothers Neal Spradlin, 28, and Seth Spradlin, 20, originally from Westfield, Ind.

Search crews pored over the rugged terrain for several days, finding no clues on the location of the plane.

The plan had originally been reported missing in bad weather in August. There were no emergency locator transmissions or radio communications from the aircraft.

Neal Spradlin has lived in Alaska for seven years, while Seth Spradlin was spending the summer there as a seasonal employee, saving money to attend college.