Editor’s Note: S ign up for Unlocking the World, CNN Travel’s weekly newsletter . Get news about destinations, plus the latest in aviation, food and drink, and where to stay. CNN  —  As millions of Americans take to the skies during what’s shaping out to be another summer of high temperatures, some will likely be searching for easy travel hacks to help make their journeys a little less painful. Among the many flying tips making the rounds in recent years on TikTok, this one continues to pop up: