Just my take on this is that it would have been true 18-24 months ago. F9 changed their business model and Spirit pulled out of so much of the market so that its not really overlapping anymore. Both stayed out of each other's hubs and I spotted how F9 would dabble in some markets Spirit did well in such as OAK, and then would quickly back out and send most of their seats to SFO. They really haven't competed much other than in LAS and ORL, and neither of those markets suffer from a lack of options. If F9 suddenly decides it needs to start flying into FLL I might believe it but I think their current out and back model serving some fortresses like ATL and DFW are here to stay. That probably means fare increases and no one will really notice because it still might pencil out to be cheaper if the majors are raising their prices too.

People in the Las Vegas tourism industry are really worried about how this will impact them and they might be right to be worried. Spirit was good for volume and low end hotels.