Question: Which Callsign has an IATA of TR?
SQL: SELECT "Callsign" FROM "2-18952243-3" WHERE "IATA" = 'TR';

Question: Which Commenced operations have an Airline of Valuair?
SQL: SELECT "Commenced operations" FROM "2-18952243-3" WHERE "Airline" = 'Valuair';

Question: Which IATA has a ICAO of SLK?
SQL: SELECT "IATA" FROM "2-18952243-3" WHERE "ICAO" = 'SLK';