The three-letter airport codes are known as IATA location identifiers . A new system is being developed to replace the current system, which has been in place since 1988. Others do n't seem to make any sense , like ORD for Chicago . Airline Codes explains how each airport got its identifying code .
The three-letter airport codes are known as IATA location identifiers . Some follow a pattern like SYD for Sydney and MEL for Melbourne . Others do n't seem to make any sense , like ORD for Chicago . Airline Codes explains how each airport got its identifying code .