"Where is the airplane flying?"
Translation:Hol repül a repülőgép?
Yes, it is also acceptable with "Hova". (And that has even more sense to me.) But, please notice, that it is not *BudapestBE, but BudapestRE. As a general rule: For cities/towns in Hungary (and also for cities/towns in neighboring areas, which are now outside of Hungary, but belonged to Hungary in the past, and therefore have a Hungarian name.), the suffix pair "-ra"/"-re" is used. For cities/towns outside of Hungary, the suffix pair "-ba"/"-be" is used. (There are some exceptions, however. E.g. Győr and Debrecen are in Hungary, but they get the suffix "-ba"/"-be". Any city/town whose name ends with "-város", e.g. Dunaújváros, also gets the suffix "-ba"/"-be". Any city/town/village with name ending on "-hely", "-vár", "-várad", "-falva" gets the suffix "-ra"/"-re", regardless of their current or former ocation.)