飞行常客是航空公司的忠实乘客，这里介绍累计里程，兑换免费机票、商品和服务以及其他类似贵宾休息室或舱位升等权益。A frequent flyer is a loyal passenger of an airline, and here is an introduction to accumulating miles, redeeming free tickets, goods and services, and other benefits such as VIP lounges or class upgrades.