Warty,
When you are in the tower, bring up the clipboard and click on the achievement tab. At the top, you can choose show accomplished or unaccomplished tasks that will earn you achievement points. As you complete these tasks, you accumulate points which reach levels that give you stars. I think the first level is 1,500, second is 3,000, third is 6,000 and the fourth level is 9 or 10 thousand. Each level corresponds to a star designation 1, 2, 3, or 4 stars. You can click on the reputation tab and see a graphic line of your progress. You can even enter another player's name and look at their tables. It really doesn't mean anything other than it's a goal oriented feature added to the game that is fun to tackle challenges for yourself. Some of the challenges are amusing. It does in instances challenge players to try new planes and tasks that they would normally not try. Have fun with it and best of luck.
one-eye