Tucson International Airport (TUS) sits on the south side of the city, about 15 minutes by car from downtown. It is served by all the major US carriers with direct flights from Dallas, Denver, Chicago, Phoenix, Los Angeles, Atlanta and other hubs. Phoenix Sky Harbor is two hours up Interstate 10 and often has cheaper international connections.
By rail, Amtrak's Sunset Limited and Texas Eagle stop at Tucson Station on the way between Los Angeles and New Orleans or Chicago — three times a week each direction. The historic 1907 station building, just off Congress Street, is worth a look in its own right.
By car, Interstate 10 connects Tucson to Phoenix (115 miles northwest), El Paso (320 miles east), and Las Cruces. State Route 86 runs west across the Tohono O'odham reservation to Ajo and Organ Pipe Cactus National Monument.
Greyhound and FlixBus buses serve Tucson from Phoenix, El Paso, Albuquerque and Los Angeles.