If you are coming into the region both Queenstown and Dunedin Airports are about an hour by road from each end of the track, Clyde or Middlemarch.
If travelling from overseas, you can fly from Australia direct to Queenstown, Dunedin or Christchurch which is the main international airport in the South Island.
You can hire rental vehicles at each airport, or catch shuttle buses to/from either end of the Trail. The closest airport to Clyde is Queenstown – “the Adventure Capital of the World” and would be an exciting add-on to your trip.
If starting from Dunedin airport you could catch a shuttle and spend some time in the city. Dunedin is a beautiful Victorian city, its Otago Peninsula is very popular with eco-tourists.
You could also plan an airport-cycle-airport trip – fly into one airport and fly out from the other.