According to Princess Cruises, which confirmed in a statement that its passengers were on board the two planes, the Royal Princess left Vancouver on Saturday and was set to arrive in Anchorage on May 18.
Cindy Cicchetti, a passenger aboard the Royal Princess, told AP the ship captain announced that two planes were in an accident Monday.
The Federal Aviation Administration says it isn't immediately known what caused the crash.
1 person dead, 1 missing after float plane crashes near Gold Bridge, B.C.
The U.S. Coast Guard, partner agencies and volunteers are now looking for three missing people following reports of two floatplanes colliding around George Inlet near Ketchikan, Alaska.
Eleven people were inside Taquan Air's single-engine de Havilland Otter DHC-3 when it went down. Ten passengers from the excursion sold through Princess, and a pilot, were onboard that plane.
The Ketchikan-based operator of the larger plane, Taquan Air, said its pilot and nine passengers had been accounted for, and one passenger remained missing.
The Coast Guard said it had launched a helicopter crew and two boat crews from its Ketchikan station to search for the missing. That aircraft was a de Havilland DHC-2 Beaver, which was carrying cruise passengers on an independent sightseeing tour.
At first report, 10 people were accounted for, according to the Coast Guard.
Clint Johnson, chief of the National Transportation Safety Board in Alaska confirmed that he could only provide "sketchy details" but that the agency is sending a team to investigate the crash sites. Floatplanes have pontoons mounted under the fuselage so they can land on water. Ten others have been hospitalized in Ketchikan, one in critical condition.
Spokeswoman Mischa Chernick had no other information on other passengers and referred questions to the Alaska State Troopers.
A total of 16 people were on the two planes. The Otter was on the other side of the inlet, with 10 people on shore nearby.
The two aircraft came down in the sea off the southeastern coast of Alaska, around 25-30 miles (40-48km) northeast of the city of Ketchikan.
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