The classical theory of atmospheric flight mechanics is introduced. The kinematic description of a rigid aircraft is first described using Euler angles. This is followed by the derivation of the Newton-Euler equations describing the aircraft dynamics, with a discussion on the external forces appearing on the vehicle. Steady-state flight conditions are discussed next and used to introduce the concept of load factor and the maneuvering envelope of an aircraft. Finally, dynamic stability is described for both the longitudinal and lateral problem.