"For the folks we're looking for, the challenge that they're dealing with is cold water".
Both planes were carrying cruise passengers from the Royal Princess cruise ship who were taking aerial tours around 1 p.m., said Princess Cruises in a statement.
The US Coast Guard confirmed on Tuesday one of four people killed was an Australian but gave no other details.
The Royal Princess cruise ship, which left Vancouver bound for Anchorage on Saturday, is schedule to return to Vancouver on May 25. The ship is continuing to its next scheduled stop of Juneau.
"The Misty Fjords National Monument is home to some of the most dramatic scenery in Alaska, and only by air will you be able to fully appreciate the dramatic beauty of land, slowly crafted by the hands of nature over tens of thousands of years", says the cruise line in promoting the tour. Ten people have been taken to hospital with unspecified injuries. As of Tuesday night, three had been discharged. The Coast Guard is still searching for two passengers, one Australian and one Canadian.
Betty Hill, a passenger now on the Royal Princess from California, said the news was announced to cruise passengers around 6:30 p.m. Monday.
The Coast Guard said it was "unaware" of why and how the planes collided. At the time the planes were operating excursions booked by the passengers from Carnival-owned Princess Cruises.
The discovery of the bodies closes the search at the scene where the two seaplanes crashed after colliding over the inlet waters near Ketchikan, in southeastern Alaska, said Matthew Schofield, a U.S. Coast Guard officer.
At least 10 others have been hospitalised, according to the US Coast Guard and Federal Aviation Administration officials. "This is not the outcome we hoped for and extend our deepest sympathies during this very hard time".
The Ketchikan-based operator of the larger plane, Taquan Air, said its pilot and nine passengers were rescued and receiving medical attention, but one passenger's fate was unknown.
A spokeswoman for the flightseeing company said Taquan has suspended operations while federal authorities investigate the deadly crash.
The debris field was about 300 metres wide and 800 metres long, with doors, seats and life-jackets strewn in a way that indicated an aircraft had come apart in the air, Kiffer said.
There were no cockpit voice recorders or flight data recorders on either of the two planes, Homendy also said during the news conference. Neither plane was required by regulation to have such recorders, she said.
Knudson says the Beaver had been flying at a 3,300-foot altitude.