Industry is proposing touch-based solutions to modernize the flight management system, a necessary step to cope with increasing demands on lateral navigation as airspace congestion grows. However, research evaluating touchscreen effectiveness for navigation tasks on the flight deck is lacking. The SIMONA Research Simulator was used, with 12 commercial pilots participating in a within-subjects experiment to evaluate a touch-based navigation display, compared to a conventional interface. Participants were faced with a lateral weather avoidance re-planning task at varying levels of difficulty. In addition, Fitts’ law and the Decision Ladder were used to provide a theoretical basis. Results show that, where ample time is present to execute route adjustments, a touch-based navigation display is a promising replacement of the control display unit. However, for time-critical tasks participants failed at avoiding weather, providing more inputs and scoring worse on secondary task and mental effort rating. A more direct control of the aircraft was necessary, such as the heading select mode. Touchscreen interfaces are very promising; however, industry is urged to carefully determine which tasks are suitable for touch input.