Gulf Air uses ***American Airlines*** as its codeshare partner to New York - JFK, Newark, Boston and Los Angeles. All codeshare services use ***London*** Heathrow Terminal 3 as the connecting point between the Gulf and the USA. Flights operate in the GF5100-5199 range.
http://www.gulfairco.com/guide/codeshare.aspI don't understand what codeshare is.