Helena is served by Helena Regional Airport (HLN), a small facility about 4 kilometers from downtown with direct flights from Seattle, Salt Lake City, Denver, and a handful of other western hubs. If you're flying into Montana for a two-park trip combining Glacier and Yellowstone, Helena sits almost exactly between them and can make sense as a midpoint stop.
By car, Helena is on I-15 — about 2.5 hours south of Great Falls and 3 hours north of Butte heading south toward Yellowstone. The drive from Missoula via US-12 over McDonald Pass is scenic and takes about 1.5 hours. Greyhound and Jefferson Lines serve Helena with buses from Billings, Missoula, and Butte, though service is infrequent.