Don't worry if you forgot to pick up some huckleberryjam in Missoula before you left. They sell it in the gift shop after you go through security, and you won't have to check it.
Make sure you give extra time for AM flights. Never know if Security will be open or closed and it will take a few minutes to figure out your gate as they are not marked well.
Not sure what everybody is bitching & moaning about - been through hundreds of times, TSA is less strict than the other super populated airports. No need to show up 2 hours early unless you want to.
The observation deck on the 2nd floor is a nice touch. Otherwise, this airport feels like it was designed by someone who has never designed a building.
I can get through security here from curb to gate in 15 mins with checked bags. It takes my friends longer to drive home from the airport than it does for me to get through security.
Unlike NYC airports or other major hubs, the TSA agents at MSO actually make you remove liquids from your bag and carry your boarding pass through the metal detector for an additional verification.
Alaska Airlines's gate is actually up the stairs from security, over the walkway and back down the stairs. A little annoying but not as annoying as ending up back outside security again!