Specific skill types do not have an effect right now as pderuiter mentioned but the combined skills of an employee does. Each job has a certain amount of energy it requires to be completed (except for timed ones, take ramp agents or janitors for example, when they perform their job they push in a standard amount of energy plus a skill multiplier, that multiplier depends on the collected skill set of the employee. So, the smarter and better your employee is the quicker the job will get done.
It’s not that obvious right now and is quite basic but it has the ground to become very elaborate. For example, moving ahead quite soon we will implement passengers having experiences from their interactions with employees so their pleasant skill will have an impact here.