Abstract: Devices and techniques are generally described for on-time performance impact evaluation. In some examples, first flight plan data that includes a plurality of scheduled air-based routes may be determined. A first route of the plurality of scheduled air-based routes may be selected for a first package. First scan data related to the first package may be received. A first slack time associated with the first package on a first flight of the first route may be determined based at least in part on the first scan data. The first package being assigned to the first route may be evaluated based at least in part on the first slack time.