How many Earth years did it take the rocket from Krypton bearing the infant Kal-El to reach Earth?
The references below all appear to base their info on the first Christopher Reeves movie.
According to this link, the flight took two years.
However, according to this link and this link, the flight took three years. Don't know if one Wiki derived it's info from the other or if they both independently derived info from the movie. Unfortunately, I don't have copy of the movie to check it out myself.
One thing I seem to recall from the move is the image of Jor-El (when his image first appears in the fortress of solitude) tell Kal-El (Superman) that thousands of years would have passed on Krypton. If that's a reasonably accurate memory, would imply that the 2-3 flight time years experienced by the infant Kal-El were either a time-dilated measure or that Kal-El passed through some type of wormhole where the two ends were in different times. But that's pure speculation on my part.
At the speed of light, the length of time experienced by the baby would be a couple of years, but outside of the ship, where the time dilation does not occur, 20,000 years or more would have passed.
So, it took 20,000 years or so to reach Earth, but the baby only aged 2 years in the time protected ship.
I recall an origin story where Jor El and Lara are discussing Earth and Jor El mentioned that by the time Kal reached the planet, its inhabitants will have evolved into organized societies.
In episode 1 (February 12, 1940) we learn that the planet Krypton is in our solar system
Narrator: "As our story begins, we ask you to come with us on a far journey, a journey that takes us millions of miles from the Earth where the planet Krypton burns like a green star in the endless heaven."
and in fact is a Counter-Earth:
Jor-El: "A planet smaller than our own, situated on the other side of the sun."
From this one would expect that the journey would take some months, at most a couple of years. However, in episode 2 (February 14, 1940) we learn that it took much longer than that, something like 20 years if we assume that Kryptonians grow up at about the same rate as Earth people:
Narrator: "During the long journey of the rocket ship to the Earth, the child has become a man. The rocket landed in a [???]. Superman stepped forth full grown to explore this strange new world in which he found himself."
Hypothetically 200000 passed by Planet Krypton's timepassing standards inside its area, but the timepassing flight lasted about 3-2 years which means that the flight tranportation which carried Superman traveled somehow faster than speed of light theoretically creating a wormhole according to my thoughts. So, it made Superman arrive at modern Planet Earth.
In 'Man of Steel' with Henry Cavill, humans find Zod buried in ice nearly 20,000 years old. Also, in the movie Zod is sentenced to Somatic Reconditioning soon after "Superman" is sent away like a baby Moses on a cosmic river. So yeah, there would have to be some worm-hole time-loop going on if it only took 2-3 years for Kal-El to get to Earth.