Question: What is the ICAO with commenced operations before 1989?
SQL: SELECT "ICAO" FROM "2-15620088-1" WHERE "COMMENCED OPERATIONS" < 1989.0;

Question: What is the lowest commenced operations that has a NOUVELAIR callsign?
SQL: SELECT MIN("COMMENCED OPERATIONS") FROM "2-15620088-1" WHERE "CALLSIGN" = 'NOUVELAIR';

Question: What callsign has commenced operations in 2011?
SQL: SELECT "CALLSIGN" FROM "2-15620088-1" WHERE "COMMENCED OPERATIONS" = 2011.0;