The Flying Machine Boys on Duty; Or The Clue Above the Clouds

The Flying Machine Boys on Duty by Frank Walton follows the adventures of three boys Jimmie Ben and Carl who are aviators on a mission to the Pacific coast. They are tasked with finding two criminals Phillips and Mendosa who are believed to be hiding in the Sierra de Santa Lucia mountains. The boys encounter a suspicious aviator who seems to be following them and causing trouble. As they journey across the country in their flying machines they face challenges and mysteries including the sudden disappearance of a hospital patient and encounters with farmers who suspect them of wrongdoing. Despite these obstacles the boys press on towards their goal determined to reach the Pacific coast and solve the case. The book is filled with action adventure and suspense as the boys navigate the skies and unravel the clues leading them to the criminals' hiding place.