FANG by James Patterson

Max and the Flock are flying high over Africa, but this time they're not alone. A sky full of cargo planes accompanies the team as they bring much-needed aid to the continent's poverty stricken regions. Among the volunteers is the mission's benefactor--the mysterious billionaire, Dr. Hans Gunther-Hagen. Max is intrigued by his generosity, but there's also something about him--and his intense scrutiny of the Flock--that makes her nervous.