Geneva Airport (GVA)
Geneva has a great choice of flights to and from the UK, the US, almost anywhere - it's a hub and the flights run all year long. It is, however, a fairly long transfer from here to the resorts of the Oisans - 2 hours 45 minutes without traffic. It is right in the centre of town.
Tips from a local (who has spent too much time hanging around there): Switzerland IS expensive. Take a packed lunch if at all possible. It is home to the bad €10 sandwich. The wi-fi is however, quite good and you get 90 minutes free - there are loads of networks to choose from but the one to go for is called: "Free WiFi GVA". They have an app too - it's called "GVApp" and it's good for flight information.