The nearest international Airport is Oslo Gardermoen (OSL) which operate all major European airlines and the biggest American and Asian airlines.
From downtown Oslo, Beitostølen is operated by an Express Bus Line (6 x Daily). http://jvb.no/en/bus_routes/valdresekspressen+oslo+airport.9ufrrqz.ips
The organizer will be helpful to organize transportation by charterbus from the airport to Beitostølen when larger groups arrives. Otherwise we suggest the
competitor to use public transportation or rental car. Est. Travel Expences Transport cost (as of jan 2017) is app €75.- each way by public transportation. Charterbus organized by the organizer will be sligthly cheaper depending on how many people arriving at the same time
All major car Rental companies are situated in Oslo Gardermoen (OSL) airport https://avinor.no/en/airport/oslo-airport/to-and-from-the-airport/car-rental/
There is a maximum distance of 1,5 K from the lodgings to the stadium and most of the athletes will be going there by feet. Although the organizer will provide a shuttle-bus going every 15 minute from the lodgings to the stadium.