United Airlines and Frontier Airlines fly from Denver to Des Moines 4 times a day. Alternatively, Burlington Trailways operates a bus from Denver to Des Moines once daily. Tickets cost $90 - $130 and the journey takes 14 h 15 min.
From Union Station Track 1 train to Denver airport, fly to Des Moines airport, then line 8 bus to Des Moines. 4 h 29 min $251. From Denver Union Station Amtrak train to Lincoln, NE then bus to Des Moines, IA. 11 h 55 min. From Denver, CO bus to Des Moines, IA. 14 h 15 min $109. From Denver drive to Des Moines. 10 h 11 min $80.