On the topic of "glitch" and Frontier fare sales, the post Thanksgiving sale allowed you to price fares like Milwaukee-Appleton, and the calendar which shows you what fares are available on actual days showed real fares on various days in December and January.

It's one thing to still show routes like MKE-MSN and MKE-SDF because at least in theory one could go via Denver. But they don't even fly to ATW, so I'm curious how they could put prices on the fare calendar. If you tried to "book through", then they would not actually price it.