Originally Posted by
Scottie Dog
Airline reservation systems, and airport information screens use the IATA code of LS.
Not all airport FIDS will show the IATA. AENA in Spain will show airline's ICAO prefix for flight numbers. In the UK it is often IATA apart from a few airlines such as TUI which shows TOM instead of BY and EasyJet which shows EZY instead of U2.