As a general guide, a round-trip flight from Zurich to Khartoum, with one stopover in Istanbul, will cost around CHF 600 (USD 650) in the low season (January-April, November-December) and around CHF 800 (USD 870) in the high season (May-October).
You can find cheaper flights if you are willing to travel with budget airlines such as Pegasus Airlines or Turkish Airlines, but these airlines may not offer as much in terms of comfort or service.
It is also worth considering flying to another city in Sudan, such as Port Sudan or Juba, as these cities may have cheaper flights than Khartoum.
Here are some examples of round-trip flight prices from Zurich to Sudan, with one stopover:
* Zurich to Khartoum (via Istanbul), with Turkish Airlines: CHF 615 (USD 670) in the low season, CHF 825 (USD 900) in the high season.
* Zurich to Port Sudan (via Cairo), with EgyptAir: CHF 655 (USD 715) in the low season, CHF 875 (USD 955) in the high season.
* Zurich to Juba (via Nairobi), with Kenya Airways: CHF 715 (USD 780) in the low season, CHF 925 (USD 1,005) in the high season.
Please note that these prices are subject to change, so it is always best to check the latest prices with a travel agent or online booking website before you book your flight.