FLYING:
Knoxville: The closest airport is McGhee Tyson Airport (TYS) in Knoxville, about a 45-minute drive from the Pigeon Forge/Gatlinburg area. Although small, this airport is serviced by most major airlines. 
Nashville: Nashville International Airport (BNA) is approximately a 3.5-4 hour drive from the Smoky Mountains. Grab a rental car at the airport and drive up I-40 through the gorgeous fall foliage!

DRIVING:
The Smoky Mountains are a day or less drive from many states! 

GROUND TRANSPORTATION
Taxis and Ubers are available but are somewhat limited.  You will most likely want to have a car when visiting the Smoky Mountains so you can visit the attractions in the area.