Here goes, Hubwaves 101…
Let’s start with defining a few things:
Minimum transfer time is 60 minutes
Turnaround time of all your aircraft is 45 minutes
If you now have a bunch of flights inbound to your hub, landing at 12:05, 12:09, 12:12 and 12:15 (for instance), then the earliest departure you want to plan is at 13:16. Why? Because that way, the last arriving flight will still have a possibility of having passengers transfer to all departing flights. You take an extra minute for safety because the arrival time is rounded. It might be 12:15:29, which is rounded to 12:15. A departure at 13:15 would not fulfil the 60 minute transfer window, so transfers wouldn’t be possible. There is one exception, as plotz said, namely if passengers transfer from a flight on aircraft A to a second flight also on aircraft A, then the minimum transfer time does not apply.
Now, I defined turnaround time, and for good reason: When scheduling a flight on your aircraft, you’ll see the yellow (and later green/brown) blocks appear on the schedule. The time at the right hand side of these blocks is the ‘ready for departure’ time. This is the actual time at which you could send the aircraft flying again. For our example aircraft, this means the 12:05 arrival will be available for flights at 12:50. But since we want to make sure there are transfers to other flights we operate, we need to wait with our next departure until 13:16, as stated above. This means the aircraft has a small gap between the two flights.
Now, since we’re planning with this 1-hour gap, and doing so quite tightly, it’s very well possible that slots will become an issue. For that reason, I suggest adding some more time to a transfer time window. I operate from AMS, where the minimum transfer time is 1h30. My departure wave leaves 2 hours after my arrival wave. This allows me to schedule arrivals up to 30 (29, rounding issue) minutes after the target arrival wave, without losing connections. Or alternatively, it allows to pull some flights forward for those same 30 (29) minutes without losing the connections from my arrival wave.
Of course this sort of strategy is invariably going to leave some dead time on your schedule. My 737-fleet only operates 3 return flights per day. If operating back to back, I could operate 4 per day, with a potential 5th on 4-5 weekdays. Doing so, however, means I sacrifice a streamlined hub system completely geared towards generating connecting passengers.
However, there are also players who have created a sort of hybrid. They make each aircraft conform to a single hub wave, and then plan back-to-back flights after that to use the schedule more efficiently. It reduces time-on-ground, but also reduces the connection potential for the remaining flights.
And, on the note of connecting passengers, there’s one more thing I should note: Passengers can connect from any one flight to any other flight (provided an airline has transferring enabled, and/or an interlining agreement is active) only within a certain window. The window opens after the minimum transfer time (arrival + 60 minutes in our example) and ends 8 hours after arrival (15h in the case of the Devau game world). Any flights departing within that window are eligible for connecting passengers (see conditions earlier in this paragraph), so a hybrid schedule may still generate transfers, but the transfer time will average more around 5-6 hours for those flights.
Well, I hope that’s enough information for the moment, and that it helped you a bit. If not, let me/us know, I may be able to clarify what I wrote here with some screen shots if necessary.
edit: plotz’ post is probably a little more useful, though I hope the insight in additional scheduling strategies as well as their advantages and disadvantages is helpful.