Airlines are perhaps the companies most directly affected by the order to ban citizens of seven countries from entry into the United States, even those with previously valid visas or US green cards. The airlines have no choice but to cooperate with US Customs and Border Patrol instructions, even as they deal with passengers and, surely, employees who can no longer enter the United States. Update 12:37AM ET, January 29: CNN reports that there was some confusion at the Department of Homeland Security over whether the order affected lawful permanent residents — also known as green card holders.