Three people were still missing, US Coast Guard and Federal Aviation Administration officials said.
The U.S. Coast Guard scrambled a rescue mission after the crash, sending an MH-60 Jayhawk helicopter crew and two 45-foot Response Boat-Medium crews from its base in Ketchikan.
The Royal Princess' current voyage originated inVancouver, British Columbia, over the weekend and is scheduled to end Saturday in Anchorage, Alaska, the company said. The missing passengers were from Canada and Australia, Princess Cruises said. Investigators believe one came to rest in a lake, the other in the ocean.
"One aircraft, operated by Taquan Air, was flying a shore excursion sold through Princess Cruises", the company statement said.
A spokeswoman for Taquan Air, operator of the Otter, said the company had suspended operations while federal authorities investigate the deadly crash.
Cindy Cicchetti said the ship captain announced that two planes were in an accident Monday. "My hopes and prayers that they find the missing person [s] and the injured make a speedy and complete recovery".
An earlier report said five had died.
Officials have confirmed one of the people killed after two float planes collided midair in Alaska on Monday is a Canadian citizen. Ten people have been taken to hospital with unspecified injuries.
Coast Guardsmen were aided by volunteers in the search, said Capt. Stephen White, the commander of the Juneau sector.
(AP AAP) A file photo of a de Havilland DHC-2 Beaver, like the one involved in the collision. The Coast Guard recovered the bodies of two guests and the pilot.
The National Transportation Safety Board is to launch an investigation and do not that this is developing news with ongoing new details being released.
Expected survival time in water of that temperatures is one to three hours, according to the United States Search & Rescue Task Force website.
The company also confirmed that the three victims recovered from the crashed Beaver, including the pilot, were USA citizens, as were all the passengers aboard the Taquan Air flight.
"The worst-case scenario is they were coming straight at each other and hit head on".
The Coast Guard says six people are unaccounted for after two floatplanes went down in the water in southeast Alaska. Authorities say 10 of the people were accounted for. Their conditions were not immediately known.
It is unclear which plane carried the fourth victim.
The weather Monday afternoon in Ketchikan was partly sunny with 9 mph winds from the southeast and 10 miles of visibility, according to the National Weather Service.