Upper management is impressed with your new tools but wants more. They would like to see a synergy between point-region quadtree and the collection of flights. Using the PR Quadtree you can already search for docks near an arbitrary geographic coordinate(well, you didn't in P2, but you could have!), wouldn't it be great to do the same for flights?
Management has heard wonderful things about a 'PM1 quadtree' and thinks you should integrate one into your traffic management software. So you will. The PM1 allows for the storage of information about line segments(flights), but since you will still need to keep records on the location of isolated docks you will also add the ability to store individual points in the PM1. This will allow you to more efficiently process queries about flight locations on the map. (for instance, "What flight comes closest to point (x,y)" ) It will still be necessary to maintain a separate graph structure, which allows efficient processing of queries such as the shortest path between two points, and calculating a minimum spanning tree(and many many others).