Frequent fliers may age faster than those who keep their feet on terra firma, some research suggests. But it’s unlikely anyone would notice. It’s an Einstein principle at work, the Discover blog says. Time doesn’t pass equally for everybody. A fast-moving clock will tick at a slower rate than a stationary one. It’s called time dilation. People on commercial flights are subject to both predictions of time dilation. They’re going fast, at speeds of around 500 miles an hour, and because they’re about six miles from the ground, they’re also feeling a weaker gravitational pull. So do airline passengers age more slowly, since they’re traveling at high speeds? Or do they age more quickly, since they’re subject to less gravity? Chou did the math, and it turns out that frequent fliers actually age the tiniest bit more quickly than those of us with both feet on the ground. Planes travel at high enough altitudes that the weak gravitational field speeds up the tick rate of a clock on board more than the high speeds slow it down. But even if you traveled as much as the George Clooney character in Up in the Air, the blog says, you’d still only age 59 microseconds.