Abstract: Stochastic models of aircraft flight paths and a method for deriving such models from recorded air traffic data. Each stochastic model involves identifying the flight plan for one or more aircraft; identifying important parameters from each flight plan, such as aircraft type, cruise altitude, and airspeed; optionally identifying flight plan amendments for each flight; representing each route of flight as a series of navigational fixes; representing at least one aircraft flight parameter probabilistically; modeling realistic differences in at least one dimension between each planned route of flight and the flight path as it might actually be flown; and communicating the modeled deviations or simulated flight paths to the user. At least one aircraft flight parameter is represented as a random variable with a particular statistical distribution, such as a normal (Gaussian), Laplacian, or logistic distribution; or with a more complex algorithm containing one or more random elements.