Time travel into the future seems scientifically possible due to general relativity and time dilation, as we’ve seen experiments where atomic clocks slow by a few nanoseconds as they are jettisoned at super sonic speeds. Estimates based on extrapolation are that if one nears or breaks the speed of light, time will pass by very slowly for him while remaining the same for everyone else.
If such a traveler would fly at the speed of light for a year, he will have aged a year, but when he returns, many years will have passed by (i think over 100 but i don’t remember the figure)