American Airlines and the national airline of the United Arab Emirates, Etihad Airways, said in a statement Thursday they have agreed to share codes, enabling a customer transferring between the two airlines to purchase a single ticket for the whole trip. Etihad is "keen to grow further" in the U.S., the Middle Eastern airline's chief executive, James Hogan, said. The accord, subject to regulatory clearance, should come into effect as Etihad begins service to Chicago at the beginning of September…. re: Market Watch