I got a good question about runways and reservations today, specifically about why I’m saying that a flight can only have one runway reserved at a time. Here’s my justification.

Admittedly I’m making up stuff about runways here, since I’m not in the airline industry. But my idea was as follows: only one aircraft can reserve a specific runway at a time; otherwise there would be a collision when two airplanes tried to simultaneously land/takeoff. If there’s heavy traffic at the airport, it’s possible for several airborne flights to be “queued up” (not represented in the database) waiting to be given the reservation to land, but only one would have the reservation at any given time. Same thing for departures — there can be lots of airplanes waiting on the tarmac full of passengers and ready to take off, but who have to wait their turn to get a runway reservation so they can do so.

As for why a flight can’t reserve multiple runways, my assumption is that runway reservations are a pretty quick thing (on the order of minutes for waiting for one, and then using it and getting off the runway so other flights can use it) and therefore a flight wouldn’t “reserve in advance” a runway at its destination airport that it’s not even going to reach for several hours.