Thankfully, the entrance to to Glacier National Park gives a ticket for 7 days (I did not see tickets day-wise) : $25.
The other airports are Great Falls International Airport - United and Delta Airlines flies here : 2 hours 30 minutes from Glacier, Missoula : 2 hours 30 minutes from Glacier , Helena: 3 hours 20 minutes from Glacier, Billings - 6 hours from Glacier, Spokane - 5 hours to West Glacier.
However, if you are reaching to Glacier National Park anytime after 3pm, then its most likely that all the first come first serve campgrounds are taken, and hence you can still stay at KOA’s located at St. Mary’s or just outside the West side entrance of the park.
| First Come First Serve Camping and More...
Glacier National Park | Hidden Lake
Glacier National Park | Going to the Sun road
Glacier National Park | St Marys
Glacier National Park