Authorities say no survivors were found by the time they suspended their search late Thursday night, about six hours after witnesses say the pontoon plane plunged into the river near Germanton in Columbia County, on the Hudson's east bank 40 miles south of Albany.
It wasn't clear how many people were aboard the plane when it crashed, broke up and sank on impact.
State Police say they believe the pilot is a local resident who took off from Columbia County Airport in Hudson. His identity hasn't been released.
Divers plan on resuming the search Friday morning, when police are expected to release more information.
The Federal Aviation Administration is investigating.