SAN FRANCISCO (AP) — U.S. officials are looking into two more incidents at San Francisco International Airport where planes could have wound up on the same runway. The National Transportation Safety Board confirmed Monday that it is investigating the events from several months ago. A preliminary safety board report says that a SkyWest plane in December 2016 crossed a line that it was supposed to stay behind while another plane was taking off. The report also says that a Compass Airlines plane in February was forced to abort a landing because a Virgin America jet was lined up and waiting to take off on the same runway. Air traffic controllers received a warning about the potential conflict from an automated system and were able to redirect the Compass plane in time.Read more on NewsOK.com