The planets list does not have much usable information. I really hate that list in its imperfection.
I usually plan to use a ship for a certain planet when STARTING to build it, so it doesn't help if a ship is listed as already heading to a planet or not. Also, it might happen that a ship is en route to a planet but has to load population for a certain atmosphere at another planet first. As you cannot specify an amout to load with the "load" order, you have to manually load at that planet and can only give colonize order after this, again preventing that dumb list to display the "ship en route" entry.
Furthermore, the list/sort options suck. I am looking for a planet for my Rock colonizer. I have all 3 colonizing techs, so it is impossible for me to get a list with only Rock planets. It is not even possible to sort by Ice/Rock/Gas. The list also contains every planet in even the most remote systems where just an explorer has been. Or you have to enter these under "avoid" EVERY TURN - which also is not very user-friendly.
You cannot even enter a line of text that would display on that list. For example, if there is already a spaceport in that system. Or if a certain planet has to be urgently colonized due to political reasons rather then its resources.
To be useable, this list should at least have: user notes, more sort criterias, filters. I tried to use this list in my first games, and messed up my colonizers hopelessly. Now I have no colonizer flying around for more than 2 turns unless deliberately designed for exploration.
A small improvement, but every bit adds up
.