I ask this question every few months, and have yet to find an answer. How can you find out Frontier's actual city-to-city routes? Is there a schedule that they have to submit to the DOT?

The website is completely wrong. Some "city pairs" that they say exist do not, and others are East Coast city/DEN/East Coast city, which is worthless. You literally have to type in every potential city pair and check the calendar to see if the flight even exists.

Why do they hate their customers?

Edit: I just found a city-pair that they fly TO, but not BACK (TPA-MCI). I'm not joking. Do they have drunken monkeys throwing darts at a map?