British Airways’ two-letter IATA airline code is BA.
IATA airline designators are short identifiers used in passenger reservations, timetables, tickets, airport displays, and flight numbers. British Airways uses BA in flight numbers such as BA 001. The code is separate from the airline’s three-letter ICAO designator, which is BAW, and from its radio callsign, Speedbird.
British Airways was formed in 1974 through the merger of British Overseas Airways Corporation and British European Airways, along with associated domestic and regional operations. Its history therefore predates the current company in several important ways, even though the present British Airways brand dates from the 1970s.
A frequent mix-up is treating IATA and ICAO codes as interchangeable. IATA generally uses two-character airline codes for commercial and customer-facing purposes, while ICAO uses three-letter designators mainly for operational and air-traffic-control contexts. BA is the IATA code; BAW is the ICAO code.