Location from pokemon-unova by
An airport town in Unova's northern plains — Skyla's Gym uses an actual propeller cannon to fire challengers into battle altitude.
Mistralton is small but useful. It's the only part of Unova with regular cross-region air cargo service, and Skyla runs the contracts. Pilots drink at the Mistralton Saloon on Fridays. Tornadus reportedly nests in the mountains above the town; the weather is always a concern. The city's airstrip is how Ash's team occasionally fast-travels around Unova for urgent arc business.
Flat open fields, runways, hangars, a single control tower. Cargo planes land every twenty minutes. The Gym is hangar-shaped; inside, raised battle platforms rotate at different altitudes and a human cannon launches challengers between them.