The small-engine plane was flown by 78-year-old Russell Hazleton of Lake Winola.
Authorities say it went down just after 8:30 p.m. last night in a lake just outside Saint Louis.
Russell and his wife, Suzanne, were pulled from the wreckage and taken to the hospital.
Russell was pronounced dead at the hospital.
Suzanne is in critical condition
The F-A-A is investigating the cause of the crash.