All the dead were found at the crash site of a Cessna 180, the Alaska State Patrol spokeswoman Megan Peters said.
The other aircraft, a Cessna 206, landed safely.
The two aircraft, both floatplanes, collided Saturday afternoon about 160 km north of Anchorage, officials said.
The Cessna 180 crashed immediately and became engulfed in flames, Peters said.
The Cessna 206 was able to make it to Ted Stevens Anchorage International Airport and landed safely, according to Federal Aviation Administration Public Affairs Manager Ian Gregor.
The names of the deceased were not immediately released.
The pilot of the Cessna 206 was the only passenger on board and was not injured, said Peters. However, the plane sustained significant damage as it landed on its floats.
The FAA and the National Transportation Safety Board will investigate the accident, with the NTSB acting as the lead investigative agency.
Published 31 July 2011, 12:23 IST