This chapter describes experimental approaches exploring free-flight control in insects at various levels, in view of the biomimetic design principles they may offer for MAVs. Low-level flight control is addressed with recent studies of the aerodynamics of free-flight control in the fruit fly. The ability to measure instantaneous kinematics and aerodynamic forces in free-flying insects provides a basis for the design of flapping airfoil MAVs. Intermediate-level flight control is addressed by presenting a behavioral system identification approach. In this work, the motion processing and speed control pathways of the fruit fly were reverse engineered based on transient visual flight speed responses, providing a quantitative control model suited for biomimetic implementation. Finally, high-level flight control is addressed with the analysis of landmark-based goal navigation, for which bees combine and adapt basic visuomotor reflexes in a context-dependent way. Adaptive control strategies are also likely suited for MAVs that need to perform in complex and unpredictable environments. The integrative analysis of flight control mechanisms in free-flying insects promises to move beyond isolated emulations of biological subsystems toward a generalized and rigorous approach.