This topic has gone a bit quiet recently - perhaps we have been repeating ourselves too much.
One airport that has not been discussed here is Wanaka. This is an airport that is still looking to its future. Current services are Beech 1900Ds - some Convair 580 services have operated as charters to/from Auckland. Does this airport build lots of facilities that may not be used if the market does not develop, or does it risk having a terminal that will be crowded if ATRs or Q300s are used?
This is one airport where the Q400 with a flight time of about 2 hours from AKL would be a real benefit. If one of the airlines (could be AirNZ or any other player) does get 70 seater or 100 seater E-Jets, Wanaka might need to accept small jets to make it competitive on time with Queenstown from AKL. And if you develop the airport so that it can handle two hour flights to AKL, then SYD is only 90 minutes further away from Wanaka than AKL.
All this has to be considered against the fact that many people in Wanaka do not want to be another Queenstown. So, the question might be - what is the right size for Wanaka Airport?