Flew Frontier round trip to Vegas for my bachelor party over Labor Day weekend. Everything actually went very smoothly, and we got a huge kick out of the "happy hour any hour" menu (drank far too many bourbons). Seats don't recline, FYI.
BUT, as we're starting our descent into Vegas over the mountains, I guess we hit a pocket of colder air (it was 108 in Vegas), and the plane just flat out dropped for what felt like 20 seconds. Probably was only like 5-7 seconds, but pretty much everyone yelled. The older black lady in the window seat by me who had been asleep the whole flight jolted awake and yelled "AW HELL NAW, I ain't going out like this". Of course everyone clapped when we landed.