Can humans migrate to other planets? Why?

At present, there is no planet suitable for human habitation in the solar system, and it takes a long way to move to another planet. For example, the closest star to the sun (proxima centauri), Alpha Centauri C, is also 4.2 light years away from the sun, which means that it will take 4.2 years to fly in a light-speed plane, which is obviously not feasible.