Boeing Commercial Airplanes CEO Ray Conner, presents a model of Boeing's new 737 Max 9 to United Airlines CEO Jeff Smisek, right, during a news conference as Boeing CEO Jim McNerney looks on, Thursday, July 12, 2012, in Chicago. United Airlines and Boeing announce that United is buying 150 Boeing 737s, and is planning to use them to replace older planes that are not as fuel efficient. (AP Photo/M. Spencer Green)