Design and development of a quadrotor model-based flight control system entails the use of the vehicle's dynamic model. It is quite challenging to use the physical laws and first principle-based approaches to model the quadrotor dynamics as they are highly nonlinear, characterized by coupled rotor-airframe interaction. However, system identification modeling method provides a less challenging approach to modeling the dynamics of highly non-linear systems such as a quadrotor. This paper presents the frequency-domain system identification procedure for the extraction of linear models that correspond to the hover flight operating conditions of a quadrotor. Frequency response identification is a versatile procedure for rapidly and efficiently extracting accurate dynamic models of aerial vehicles from the measured response to control inputs. During the extraction of the quadrotor's model, flight test manoeuvres were used to excite the variables of concern for flight dynamics and control by adopting a systematic selection procedure of the model structure for the parameterized transfer-function model and the state-space model. The technique provides models that best characterized the vehicle's measured responses to the controls commands, and can be used in the design of a flight control system.