In this paper, a novel PID gain update law using linear least squares regression is introduced as an adaptive control method for autonomous helicopters. In addition, prediction analysis is conducted for error dynamics of the closed loop system using recursive linear least squares regression. Combining these two concepts with classical PID controller, an intelligent PID controller is obtained. A flight controller with three control loops is developed to demonstrate the capabilities of the controller. Finally, several maneuvers are carried out to investigate the new intelligent controller.