Six degrees-of-freedom (DoF) motions of aerial vehicles are described by a set of ordinary differential equations that are coupled and nonlinear. The usual approach of designing autonomy for such vehicles is based on linearization of the vehicle model at various trim states and formulating control problems for various objectives independently. Recent advances in nonlinear systems and control theory have provided unique ways of designing control algorithms for such systems, dealing directly with the nonlinear models without having the need to explicitly linearize them apriori. For aerial vehicle autonomy, this requires a complete analysis of the vehicle model to safely accommodate fast-changing task scenarios. Such analytic characterization helps in defining accessible regions of operations of aerial vehicles which ensures feasible and safe maneuver design. In this work, a generic integrated framework using a nonlinear system approach based on direct continuation methodology and sliding mode control has been developed for guidance and control of 6-DoF vehicles. This integrated framework has been tested for various guidance and control objectives in simulation for different classes of aerial vehicles and has also been implemented in real-time on an experimental Quanser 3-DoF Gyroscope.