This study analyses deviations from planned flights in the European space network by studying economical motivations of airlines as triggering factors. For that reason, planned and performed historical traffic data from EUROCONTROL’s DDR2 have been used to examine 579,243 flights of December 2018 by calculating their savings in terms of operational costs and en-route charges. Results show that aircraft operators are systematically achieving savings on account of reducing planned distance when performing the flight and not by cutting en-route charges, which have a significantly lower weight in comparison to pure operational costs. This seems to be triggered by a combination of three factors: the intrinsic nature of flights that are performed during low traffic conditions; the interaction of pilots and air traffic controllers that look for a more efficient operation; and what seem to be distinct legitimate internal policies of airlines that would lead pilots to behave distinguishably when facing possibilities of reducing planned distance when performing the flight. The latter has been observed by introducing a new metric called dsTS, which measures the savings achieved by an airline per nautical mile, and by appreciating a relevant disparity among their values.