Great Airport Mystery (Version 2)

The boys prepare to graduate from high school and are witnesses to a suspicious airplane emergency landing. Soon they become involved with their father, the famous detective Fenton Hardy, in investigating a theft ring only to be falsely accused and arrested. Bailed out by wealthy individuals that the boys had solved mysteries for in the past, the intrepid duo sets about to solve the thefts and clear their names. - Summary by James R Hedrick