Interstellar travel is an impossible fantasy.
If they go too far they’ll fall of the edge of the solar system.
Since we have a probe in interstellar space (past the heliosphere) right now, I'd say that your statement might be bound by the facts, and a limited understanding of the current acceleration of technology.
No one is going to jump on an interstellar liner next year, but to say that it is an impossible fantasy is akin to:
"To place a man in a multi-stage rocket and project him into the controlling gravitational field of the moon where the passengers can make scientific observations, perhaps land alive, and then return to earth--all that constitutes a wild dream worthy of Jules Verne. I am bold enough to say that such a man-made voyage will never occur regardless of all future advances."
-- Lee deForest, American radio pioneer and inventor of the vacuum tube, 1957
/johnny
We went from no space program to putting a man on the moon in 9 years. If more people actually believed we could reach a good percentage of the speed of light, and actually thought outside the box about propulsion, maybe we could start working on stasis pods for long hauls to other solar systems.
Instead of saying outright that it can’t be done.