Ok I've done the naming convention so each strip will be prefixed with a NZ and then 2 alphas and a number i.e. NZAA0, NZAA1......NZAB0, NZAB1 etc
Apart from some cleaning to remove duplicates with proper airfields and some tweaking (below), this is ready for testing.


Some further questions to help me make it more useful: The default airports don't have their 'Region' set (i.e. Rotorua can't be found by going to 'Bay of Plenty' but it can be found by choosing the city) but I can do this with these airstrips- Would it be useful? (i.e. would you start from these strips or slew/fly to them?) It could mean you could choose from a list of airstrips in your local district (I would use NZ districts rather than regions to narrow the number of strips for each menu choice)
Since there are a number of them (~3500) they will be included on the Airport list in the Free Flight dialogue box...which could make choosing a 'normal' airport a bit daunting. Would giving them a 'City' tag of 'Rural' make it easier to narrow the list?
???