The following assumptions are made regarding the problem in the vortex lattice method:
*The flow field is incompressible, inviscid and irrotational.  However, small-disturbance subsonic compressible flow can be modeled if the general 3D Prandtl-Glauert transformation is incorporated into the method.
*The lifting surfaces are thin. The influence of thickness on aerodynamic forces are neglected.
*The angle of attack and the angle of sideslip are both small, small angle approximation.