You wont find much information for the cache here but might be able to get a plane to go search for it as you have to take to the air and check out the city from above.
Tainan airport can be found at this location since 1937 it is a combined commercial and military airport. The airport has had regular flights to Taipei Songshan untill a few years after the High speed railway opened. The airport now has daily flights to Kinmen, Penghu and Hong Kong.
The cache can be found at: N 22° 5A.BCD E 120° 1E.FGH