This site is being deprecated.
Please see the official X‑Plane Support page for help.
You need to follow the instructions from Rishi's first paragraph in the above answer.
However, before you do have a look at the following https://www.youtube.com/watch?v=l9wubukUlxI from a dedicated X-plane user. As Wycliffe says "You don't have to delete X-plane again".
I have no connection with this site.
The X‑Plane installer does not infest your hard drive with shortcuts and directories. Therefore, all it takes to uninstall the program is to delete the X‑Plane installation folder by dragging it to the Recycle Bin or Trash. After you empty the Recycle Bin/Trash, the program will be removed completely from your hard drive. You can also read more here.
This site is no longer being actively maintained.