Alaska Airlines, Inc. and Delta fly from Portland to Boise every 4 hours. Alternatively, Greyhound USA operates a bus from Portland to Boise twice daily. Tickets cost $45 - $110 and the journey takes 9 h 2 min.
From Skidmore Fountain station tram to Portland airport, fly to Boise airport, then bus to Boise. 3 h 36 min $122. From Portland, OR bus to Boise, ID. 9 h 2 min $86. From Portland drive to Boise. 7 h 10 min $51.