A method of modelling a flight of an aircraft using at least one computer system is disclosed. In one embodiment, the method includes: sourcing flight details from at least one data source using at least one data acquisition system, the flight details representative of the activity of the aircraft within a flight information region, and compiling a flight model from the flight details using a processing system, the flight model indicating the activity of the aircraft over the duration of the flight in two or more FIRs or for an entire flight undertaken in a single FIR.