Botswana is located in the Southern part of Africa and shares a boarder with South Africa, Zambia, and Zimbabwe. Most of the International airlines connect Johannesburg with the rest of the world, once you land in Johannesburg you can fly Airlink directly to Kasane or fly Air Botswana to Kasane via the capital city, Gaborone.
Air Botswana has daily flights between Gaborone and Kasane, as the national airline Air Botswana is always willing to add extra flights to support tourism and business activities.
Airlink also has daily flights between Johannesburg and Kasane.
Air Botswana: https://www.airbotswana.co.bw/