Don't always rely on that. When I was booking my August trip there was only one open return flight at 9:20 in the morning. I panicked and booked it thinking that I could always change it later if something opened up. About a month after I booked, all the other flights on that day became available at the special internet price. I decided to keep the morining flight in order to avoid the afternoon thunderstorms in Orlando. Keep checking the SW site. Flights become available all the time.