Kitzbühel ski resort is 80kms from Salzburg, 90kms from Innsbruck, and 125kms from Munich. All of these cities have airports and receive traffic from European and world cities. There are rail terminals near these airports with connections to Kitzbühel; trains also connect with the resort from London.
The nearest international airport is Salzburg International, which has regular shuttles into the city, from where trains and buses go direct to Kitzbühel. At least one train per hour leaves for Kitzbühel, taking 2 hours, 30 minutes. Buses also leave from Salzburg train station and are slightly quicker than the trains, but a lot less comfortable.
By car, Kitzbühel resort is just over 1,100kms or a day's drive from Calais; while Vienna is 385kms northeast. If you're driving from Innsbruck, take autobahn A12 east to the junction with Route 312 heading to Ellmau. After bypassing Ellmau, continue east to the junction with Route 342, which you take south to Kitzbühel. From Salzburg, take the E-60, B-312 and B-161.
By rail, it is possible to leave London on a Eurostar train with connections all the way to Kitzbühel. A daily Eurostar leaves London at 17:09 for Paris. From Paris' gare de l'Est there is an overnighter to Munich from where regular Eurocity trains go to Innsbruck. From here, several trains make the one-hour trip to Kitzbühel.