Optimal control is one strategy to prepare for the preliminary design of multi-kite airborne wind energy systems (MAWES). However, the solution of an optimal control problem (OCP) can only be as good as the modeled physical constraints. This thesis intends to find a wake induction model that is sufficiently fast to work in interactive numerical optimization, while being sufficiently accurate to give meaningful OCP solutions. Work so far has determined that: a wake model is necessary, that the model should be valid over applicable wind environments, that the model should include unsteady effects. A fast wake model suitable for MAWES (an engineering induction model) has been proposed, and work is ongoing to synthesize a model with a wider region of validity.