The Senate's No. 2 Democrat asked the CEOs of United Airlines and American Airlines to answer questions on rising passenger complaints and higher ticket prices and fees. Senator Dick Durbin said on Thursday he was taking a closer look at legislation proposed in January to require refunds for delayed flights and transportation on rival carriers, and prohibiting unnecessary airline fees as part of sweeping new consumer protections. Durbin's queries come as major airlines have clashed with him over credit card fee legislation as well.