Too many already, some believe, and too many by far expected over the next 25 years.
It is a huge problem for the Queenstown Lakes District Council, and having its Queenstown Airport Corporation borrow hundreds of millions of dollars to develop Wanaka Airport - to take some of the load off Queenstown - appears to be top of its list of solutions.
But where is the rest of Otago and Southland in this?
Canterbury, with a population of just above 600,000 has one big commercial airport (not counting Timaru).
Otago and Southland, with a combined population of about 330,000, have substantial airports at Dunedin, Invercargill, Queenstown, and potentially Wanaka. And, as everyone points out, there is plenty of spare capacity at Invercargill and Dunedin.
The projection is for a rise in air passenger movements to the Lakes district from just over two million at present to just over seven million by 2045.
Even five million would be a step way too far for many residents around Queenstown Airport concerned about noise and congestion.
So, what we have is Queenstown with a potential oversupply of passengers, and Invercargill and Dunedin with an existing undersupply.
Surely, that makes one small local authority's problem a huge opportunity for the entire region. It begs an Otago-Southland strategy that will serve for decades, not a localised stopgap measure many suggest the development of Wanaka Airport would be.
But, where is the united Otago-Southland voice? Is there one; has there ever been one outside rugby since the abolition of provincial government in 1876? Was there even one then?
The Otago Regional Council is as close as the province gets to a region-wide organisation but its transport mandate extends only as far as buses.
So, where do Otago and Southland turn for leadership as a region? There is a mayoral forum, where local authority leaders meet four times a year. But, does not this opportunity, this windfall of air passengers, require some serious input from the Dunedin City Council, the Invercargill City Council, the Central Otago District Council, the Waitaki District Council, the Southland District Council - have we missed any? - who might sit down with the QLDC and plot a course?
Millions of dollars of ratepayer money have been spent over the years to attract tourists to the South.
Well, here they are. Perhaps the South as a region - rather than individual local authorities representing small numbers of ratepayers - should roll out a welcome mat that is broader than the tarmac at Frankton.
Perhaps, instead of spending money on new airports, or redeveloped airports, the money might be found to fix the road around the side of Lake Wakatipu, or through the Manuka Gorge.
Perhaps the Queenstown Airport Corporation could bump up landing fees and turn its Frankton airport into a premium destination.
There is no shortage of ideas on how to solve the problem, but there seems to be a shortage of leadership willing and able to look beyond the horizon of their own piece of Southern turf.