1. A method comprising: providing training data for training at least one mathematical model, wherein the training data is based on past flight information of a plurality of passengers, and the training data comprises a first set of vectors and an associated target variable for each passenger in the plurality of passengers; training at least one mathematical model with the training data; and providing a second set of vectors relating to past flight information of a passenger as inputs to the trained at least one mathematical model and calculating an output of the trained at least one mathematical model based on the inputs, wherein the output represents a prediction of future flight activities of the passenger.