For air travel we recommend flying into either the Santa Fe airport or the Albuquerque airport. The Santa Fe airport is less than 15 minutes from Old Town, and the Albuquerque airport is about an hour. If you plan to fly into the Albuquerque airport and aren't looking to rent a car, we recommend using Groome Shuttle Services (linked below) for a fairly economical and easy way to get to Old Town Santa Fe. (about $50/person but they often run promotions for people traveling together)
Groome Shuttles


If you want more of an adventure (read: we have no idea the efficacy of this idea, but go for it if you want), look into the Albuquerque to Santa Fe train service: Rail Runner. Note this train does not go to the airport and thus will require a short bus ride in Albuquerque.
Learn more about this option here