Reno-Tahoe International Airport: The practical commercial-airport gateway, about 36 mi east. Reserve the North Lake Tahoe Express shared shuttle to Truckee; allow at least 1.5 hours because it makes stops and winter weather can stretch that considerably. Published one-way fares have been roughly $85–99 per person, so a rental car often wins for two or more people. There is no direct public-transit link from RNO to Truckee.
Sacramento International Airport: Best for Bay Area/Sacramento-side itineraries, but it is about 120 mi away and not a quick airport transfer. Rent a car and allow roughly 2–2.5 hours in clear conditions; in winter, build in far more time. Without a car, use an Amtrak Thruway connection via Sacramento/Capitol Corridor services to Truckee rather than trying to assemble local buses.
Truckee Amtrak Station: The California Zephyr stops once daily in each direction between Emeryville and Chicago. The station at 10065 Donner Pass Rd is across from historic downtown, so it is the rare arrival point from which a car-free first evening is easy. Book early for sleeping-car space and peak holiday dates; the train is scenic but not a fast or especially frequent regional shuttle.
Truckee Tahoe Airport: Useful only for charter/private aviation and limited Surf Air service, not as a normal scheduled-flight option. It is not a substitute for RNO or SMF.