Airport scalpers resell airport tickets. Yellow cattle originally meant yellow cattle, and later it became synonymous with yellow cattle. Cattle first sold food stamps, and later began to develop into air tickets, train tickets, movie tickets, concert tickets and so on. Make money through the price difference. It is called scalper because in the old society, all the people who sold train tickets were drivers, all wearing yellow vests. Now scalpers have developed into an industry, mostly unemployed and local ruffians. They will buy tickets in large quantities through various connections, usually through illegal means, and then sell them to those in need at high prices.