A weakness with the Swedish Transport Administration’s model for long-distance trips is that it onlyallows for one mode of transportation per trip. A long-distance trip usually consists of several modesof transportation, while the current model does not allow modelling of, for example, a flight with aconnecting car, bus or train transfer. This is problematic as a significant part of the generalized costof travel can be derived from an access trip.The master thesis has been devoted to studying how a model for choice of access mode anddeparture airport can be designed. The work has been limited to study long-distance trips starting inStockholm county, carried out by residents of the county. The airport choice has been limited toArlanda and Bromma Airport.In a literature review, the underlying mathematical theories which the project is based on arepresented. The theory originates from the work on discrete choice models by Daniel McFadden,which later was further developed and summarized by Kenneth Train. By studying previous researchdealing with modelling of access mode and airport choice, it can be concluded that there is noobvious approach to model design, apart from the fact that the model should be based on the logittheory.The observations on which the model is estimated are retrieved from travel surveys conductedduring 2011-2016. A cost estimate for the modes of travel included in the model has been donemanually. Travel times for all modes have been generated using the Swedish TransportAdministration’s regional base model for Stockholm County dated 2014, using the macro simulationsoftware Emme.Out of all the estimated models, one model is presented as the best and final one. It is a multinomiallogit model divided into two segments, one for business travelers and one for private travelers. Themodel is analyzed by calculating value of time, cost- and time elasticity for each of the alternatives inthe choice set. For some of the alternatives, the value of time is relatively high, which is addressed inthe concluding discussion.