If you fly up into a planet...

"Up" and "down" are not universal absolutes. They depend on local gravitational conditions- so in one part of the universe, up and down might be very different to another, depending on how gravitational fields are set up in those areas. This is true even on Earth- "up" and "down" are not the same direction at all points on the Earth- someone in the southern hemisphere perceives down in a different direction to someone in the north.

In the scenario you described, you pretty much arbitrarily defined the initial approach to the planet as "upwards"- there is no particular reason why it should be defined as such, other than that an observer in the spacecraft might perceive it as above them. An observer on the planet would always have viewed the spacecraft as above them coming down.

When you are in SPACE, UP and DOWN are all relative to YOU.

While the planet seems to be ABOVE you, if you were standing on the planet your space ship would appear to be UPSIDE DOWN.

When you are in orbit, you are in a state of FREE FALL. You are ALWAYS falling! But as you fall, the planet moves out from under you, so you fall in a circle around the planet -- the ORBIT.

SO -- if the planet appears to be ABOVE you, simply turn your ship over so that it is "right side up" RELATIVE TO THE PLANET -- and land normally.

UP and Down is relative to objects, stars and celestial bodies around you. As the gravity pulls your craft down you go down approaching its center of gravity. Approaching a planet has no up or down ... but relative to the Polaris star for example changes that.

If your in a strong ship you wont just fall down but if your in a weak ship or in no ship at all you'll burn into fire and fall fast