在东航随心飞之后，航空公司推出随心飞套票成了一个趋势。中国南方航空周二也推出快乐飞套票，至少8家中国航空公司已推出随心飞产品。请看本报昨日的报道：

China Southern Airlines Tuesday rolled out an “all you can fly” pass, becoming the latest in a fleet of cash-strapped carriers to join a promotional craze that analysts say has helped revive a coronavirus-ravaged air travel market.

At least eight of China’s dozens of airlines have introduced similar deals since June, often priced around US$500 for, in some cases, unlimited flights. Industry watchers say the packages have been a shot in the arm, with costs offset by otherwise empty seats being filled in a country where daily flights last month recovered to 80 percent of pre-coronavirus levels.

报道中的a shot in the arm本意是“注射药物”，引申为“激励措施、兴奋剂”。例如：

The good test grade was a shot in the arm for Gary.

考试的好成绩对于盖瑞是莫大的鼓励。