If you look at the statistics of your airline you will see many tabs such as
Richest CEO .. you are number 3/213
Average fleet utlization ... 112/213
Average fuel burn per pax ... 115/213
Bacically the better you do on the statistics the better airline score you get... I am not sure about the formula this is calculated from either.. but the score increase as you climb the statistics. On that note.. I have always laid in the middle of the score, I've never climbed to the top yet... but in the beginner worlds it is more about working stratigies and learning the game, you do not get any achievements in BWs for chasing scores.