Also, since there is no nonstop PRG-CLT service on any carrier, you might look into redeeming miles on Lufthansa for PRG-MUC-CLT. Chase UR points transfer to Star Alliance member United; Capital One miles transfer to Star Alliance member Avianca. Neither UA nor AV collects carrier surcharges on its awards. But dealing with Avianca's LifeMiles can be challenging, so do your homework before deciding whether to use LifeMiles.