Wizzair don't fly to Sarajevo, they have a base in Tuzla for Bosnia, Sarajevo airport have very very high landing fees. Wizz have approached the airport but they don't seem willing to accommodate them. Most likely at the risk of upsetting the Lufthansa Group as they basically have a monopoly with Austrian, Lufthansa and Swiss flying into the airport, along with fellow Star Alliance Partner Turkish. Also, for Bosnians to visit the UK they all need visas unfortunately so it does not make it an easy or cheap process for them to come and I'm not sure how big the demand would be for people in the UK visiting Bosnia, though it does have some amazing scenery and lots of snow in the winter for skiing.