The Secret Of Flight X-71 - S. J. Spudrick - Bog

Sabotage! Kidnapping! Mystery!In the middle of a summer aeronautics class at the Bayport Airfield, Frank and Joe witness a dangerous plane crash. But after they help rescue the plane's passengers, the real mystery begins. Not only is the plane a technical marvel, but its crew and cargo are keeping secrets as well. Who are the passengers of this experimental jet? And why does someone want them out of the picture for good? A kidnapping and series of deadly traps mean Frank and Joe must form an alliance with strangers and discover who is behind these attacks, before it's too late!