Fez has an airport, but it is rather small and it only serves national flights. If you want to flight to Fez from abroad, you will have to get first to Casablanca.
Fez can be reached also by road or by train. Trains will take you to Meknes, Rabat, Casablanca, and further south, to Marrakech. There are also several buses to the mentioned destinations. It will take you from a couple of hours (Meknes) to eight or more hours (Marrakech). It is also possible to get to/from the other Moroccan cities by taxi. Renting a taxi will not cost you much more than a bus if there is four or five of you. Ask your hotel, they will look for a "Grand" taxi for you.
It is also possible to rent a car in Morocco. Roads are in very good conditions. The only problem is that traffic in the Moroccan cities is somewhat chaotic.