There is no comparison of flying from Denver to Cancun via Southwest to flying Frontier. The seats are a 100% better. Much less leg room problem. No checked bag fee. Free coffee sodas and snacks that you don't get with Frontier. On frontier, you find out what sardines feel like in the can. The crew are always in a good mood. I had two coupons for free drinks going and coming back and they didn't take the ones coming back. Just a good experience that you don't get flying Frontier. Do yourself a favor and fly Southwest to any of your destinations.