Runways should not be considered roads. This causes issues when you want to script placement of objects on roads (but not runways).
In fact using IsOnRoad player for a player standing on a runway returns false. So there appears to inconsistent implementation of what a road is.
Considering JETS DLC, might be useful to have:
1. nearRoads not return runways OR
2. Add a new function isOnRunway where you can check if an object or position is on a runway