Kalispel (FCA/GPI) is about a 15 minute drive to downtown Whitefish, however there are several other airports within a reasonable distance. These airports include Great Falls (GTF), Helena (HLN), Missoula (MSO), and Bozeman (BZN).

There are some Ubers/Lyft in Kalispell and Whitefish, but it is a small town so availability might be limited. I recommend renting a car so you can explore Whitefish and all it has to offer.