That covers you if the US flight is cancelled. But do they owe you credit if the flight is delayed so long that the only way they could get you to your destination that same day is to put you on another carrier? My 4:15PM flight was delayed over two hours and I would have missed connecting to the day's last flights into Tampa. They instead put me on DL and I got home. Not a bad ending but now I find myself two segments shy of requalifying.