These are just IATA (International Air Transport Association) codes. They are used in aviation to identify and differentiate airports. That’s why a Surabaya Juanda Airport to Dallas/Fort Worth Airport flight would often be abbreviated as a SUB to DFW flight. Houston George Bush Intcntl Airport (IAH), Austin Bergstrom Airport (AUS), Houston Hobby Airport (HOU), San Antonio Airport (SAT), Dallas Love Field Airport (DAL) are some additional IATA codes for airports related to your trip. Find deals