Schematic representation of changes in nearest-airport areas. (A) Catchment areas of three existing airports, assuming nearest airport chosen. (B) Landside access changes in catchment areas nearest to each of four airports after construction of new airport 4. Landside changes due to reductions in distance to airport for places formerly closer to airports 1, 2 and 3. Figures in percent show illustrative percentage landside distance reductions to nearest airport. Note all catchment areas experience airside access changes due to new airport 4. (C) Buffer zone around mid-way lines between each airport excludes places close to old and new airports. Example illustrated approximately for absolute difference in distance <60%.