While out and about exploring Christchurch, GeoHubby and I always spot little places and say "That's a good spot for a cache". This is one of those spots. A nice quick park and grab.
You can in fact see planes here, and possibly birds too, if you are facing South. You won't find the cache facing that way though. But after finding the cache, it's a great spot to stop and watch the planes land, or take off, depending which way the wind is blowing.
Please make sure you fully pull off the road onto the grassed area, and mind little ones, this is a very busy area.