Frontier's clientele -- which, on average, seems to consist of a high proportion of infrequent flyers -- probably does check bags more frequently than "frequent flyers" at other airlines check bags. That said, checked bags aren't a lot cheaper. Does Frontier even have a fixed bag fee these days? On my last Frontier trip, it was $40 for a carry-on and $42 for a checked bag. Obviously, the checked bag only makes sense if you're going to carrying all your worldly possessions with you or you're smart enough to consolidate your entire party's belongings into one ginormous bag instead of multiple carry-ons. In any event, it's obvious that Frontier's sky-high carry-on fee greatly discourages people from bringing carry-ons. I agree this is good for everyone else who's just bringing a backpack -- there's always tons of room because there are so few full-sized carry-ons -- but I think it's a screwball way to do business.