According to Einstein flying close the speed of light theoretically slows time, traveling at the speed of light makes time stand still and traveling faster reverses time, but this is impossible because mass at these speeds becomes infinite. Maybe.
Experiments with atomic clocks on planes and on earth show the second get slow so same thing should work at extreme speeds. A living time traveler is Russian cosmonaut Sergei Avdeyev who was in orbit 748 days and got younger by one-50th of a second.
Stephen Hawking said traveling back in time is impossible. Some say all of space and time exist at once and time travels are something in our minds.
A new movie opens the subject of time travel again, The Time Machine, based on H.G. Wells' novel.