large scale problems in industry that are solved on a routine basis.
Nevertheless, there is ongoing research in this area, partly motivated by
improvements in modelling and the mathematics of the underlying theory,
partly induced by increasing fleet sizes and the neverdecreasing
complexity of the rule systems. We give an introduction into the
mathematical modelling process which is common to all major airlines and
point to the differences in the models in Europe and in the United States,
and their consequences for the solution process.