My son is in China to study Mandarin. He holds U.S. passport. He has a single entry Chinese visa. Now he wants to take a trip to Taiwan when he finishes his study. He has a return ticket to fly from Beijing to Guangzhou, Guangzhou to Los Angeles. He needs to stay at Guangzhou airport for a day and wait for connecting flight. He will buy a round-trip ticket from Beijing to Taipei and return to Beijing. Then fly from Beijing to L.A.. Does he need another visa to get to Beijing airport? Will they let him board the airplane? What about at Guangzhou? I ned this reply ASAP.