I was having a think about “W-Pattern” flights as well recently. Flights going A-B-C-B-A, operating using an aircraft based at A. This is something that could be quite nice to introduce as a stepping stone to having a based aircraft, having your airport be the “B” in the above scenario.
In practice, you would get two flights. Flight 1 would arrive from A and depart to C. Flight 2 would operate later in the day, arriving from C and departing to A. There would be a mandatory minimum separation between the two flights to represent the time taken to fly to and from C, giving the impression that the two flights are operated by the same aircraft. Movements like this do happen in the real world and might be relatively simple to introduce if you have some simple rules for scheduling (e.g. Flight 2 must arrive at least 5 hours after Flight 1 departs).
Going back to the video, airlines could build up banks through use of similar rules on the contracted flights. “Must arrive between 9am and 11am” could be one, with another rule “must depart between 12noon and 2pm”. This potentially has the aircraft sitting on the tarmac for several hours if that’s how it has to work in the schedule.