Being from Denver I can never complain about new flights, but with Frontier, United, and Southwest all huge in DEN i'm not sure how much longer this is continue. Not only do all three have their fair share of flights to the same destinations but, many routes such as BOS, NYC area (Jetblue), SLC (Delta), SEA PDX (Alaska) MSP (Northwest), Dallas+ Houston+Chicago (Ameraican,Continetal) off the top of my head are served non-stop by 4+ carriers, which seems like a huge capacity in between cities. Frontier basically has no where else to go, United still has IAD, LAX, and ORD to fall back on, and with southwest still growing it is going to be a very interseting market in the next few years.