There are still regular schedules. Flight 1172 will have the same scheduled route and time one day after another. But with computers, the visibility into the schedule is both obscured (because they’ll show you only the flights with open seats) and less necessary (because they’ll show you only the flights with open seats). Crewing requirements mean that it’s important to have some stability in operating schedules. The stereotype of flight crews staying in a hotel at the far end of their flight is only the case for long-haul flights which comprise a minority of flights. Most crew will be on an out and back itinerary for their working days, sleeping in their own beds at the end of the day.