I think it would be possible, but the distances are massive between planets so it would take a long time. You would have to pack extra sandwiches for the flight. For example it would take 18 years for a jet plane to reach the sun
Possibly, but we probably need to invent a new way to propel our space vehicles. Chemical fuels (like in normal rockets) just aren’t doing the trick anymore! Rocket fuel is heavy so we need something new and light, like a black hole engine (~40% efficient) or an anti-matter engine (95% efficient)! or we can just start working on a “stargate”… BTW it is harder to get to the sun, than it is to get to the outer solar system. Earth is orbiting very fast around the Sun so you have to get rid of a LOT of kinetic energy to get to lower orbits and reach the Sun.