From The Perry Mason TV Show Book (revised)
Dr. Stacey Fielding is supposed to be flying his own plane to Salt Lake City on business. Monkey business is suspected when the plane crashes and the body is found with Veronal poisoning. His wife Miriam is arrested for murder since the last thing Stacey drank was whiskey from a flask she had given him.
But Miriam is cleared when Perry contends the body has not been positively identified as her husband, and Perry's second guess as to who the body is is also incorrect, causing her to be rearrested. To prevent her from being put on trial a third time, Perry has to solve the mystery.