Great question - BFS to MLB just means Belfast Intl Airport to Melbourne Airport. Now you’ll know what these unique codes when you look for flights! Belfast City Airport (BHD), Glasgow Prestwick Airport (PIK), Londonderry Eglinton Airport (LDY), Isle of Islay Glenegedale Airport (ILY), Campbeltown Machrihanish Airport (CAL) are other airports near this flight route and their unique identifiers/IATA codes.