Abstract The effects of aerodynamic model assumptions on the optimal wing-kinematics for hovering micro-air-vehicles are determined. Specific kinematic functions for the wing motion are specified and the parameters of these functions are considered as the design variables for the optimization problem. Four aerodynamic models having different levels of fidelity that capture various physical aspects of hovering aerodynamics are considered to assess the effects of these different aspects on the optimal wing kinematics. These physical aspects include the leading edge vortex, rotational lift, non-circulatory contributions, and flow unsteadiness. Conventional models for pitching wings are not adequate as they predict considerably high rotational lift and too little power requirements, which makes the optimizer, unrealistically, leans toward almost pure rotational motion with little flapping. In addition, quasi-steady modeling overestimates the generated lift and, as such, leads to a more optimal, but unrealistic, performance. Therefore efficient unsteady modeling is essential in design optimization of flapping-wing micro-air-vehicles.