Hi Warin61,

Thought I'd submitted this, but either I didn't or it disappeared.

I think (it was a very long time ago), the existing tags caused the map to render with thousands of airplane icons at most zooms, and the renderer folks view was that it needed better tagging. In reality these airstrips are farm fields that are flat and are/have-been very rarely used to land a plane on for agricultural crop-dusting.
I didn't unilaterally make a decision, it would have been discussed on https://groups.google.com/forum/#!forum/nzopengis and we'd normally consult other OSM lists/etc regarding complicated tagging issues. I can't recall the details though.

IIRC any meaningful airfield (even the small grass strips) were tagged differently, but it's quite possible we missed something. There were runway & airport point layers from both Topo50 & Topo250. And it's quite possible LINZ has changed their data schema since then too.

Not sure if that helps or not?