This paper presents a modeling framework for evaluating the sensitivity of airline schedules to the congestion pricing of airports. The framework allows airport agencies and aviation management authorities to examine the effectiveness of airport pricing schemes in reducing flight delays at congested airports. The framework replicates airlines' schedule planning decisions in a free market as it considers the effect of applying time-varying landing fees and associated delay externalities. The framework adopts the concept of Wardrop's network equilibrium as the basis for modeling competition among air carriers. A hypothetical airline network with two competing air carriers is used to illustrate the capabilities of the developed framework. The results of the conducted experiments show the importance of considering the network effect in developing effective pricing strategies.