© 2022, American Institute of Aeronautics and Astronautics Inc.. All rights reserved.This paper presents a generic helicopter dynamics model that satisfies the fundamental requirements such as generalizability, simplicity, good accuracy, and low computational complexity of a model for trajectory based applications and onboard/intelligent avionics. The helicopter model is obtained using both hover and forward flight dynamics. It is defined as a hybrid system to manage the transition between these flight regimes. By this way, it can operate in different flight regimes. A parameter estimation procedure is also presented to obtain the barely known model parameters via well-known performance constraints to improve the generalizability of the proposed model. Hence, the model can be easily used to mimic the dynamics of different helicopter types. And, a nonlinear control structure is designed to ease the trajectory generation process by separating the management of the longitudinal and lateral motions and to improve the system performance by eliminating the chattering problem and high overshoots in the open-loop system. The simulations show that the performance of the system is improved, the closed-loop system leads to feasible and practical trajectory generation for real-world applications, and the parameter estimation procedure does not jeopardize the accuracy of the system, it leads to consistent results with real performance limits of the helicopter.