A system and method for dividing a flight path into flight segments, wherein the flight path comprises a route between an aircraft takeoff and a runway landing; receiving a historic transit time and real-time transit time of a target aircraft class, for each flight segment of a current flight; determining a differential time for each flight segment by comparing the real-time transit time and the historic transit time; applying the differential time to each flight segment to adjust an estimated transit time for each flight segment; determining an estimated ON time for the aircraft by adding together all of the estimated transit times from each flight segment of the flight path; and determining an estimated IN time for the aircraft based on the estimated ON time and an estimated ON to IN time. The system includes a calculation engine for performing the steps of the calculation.