According to the Guide this badge is for the number of SkyDocks unlocked. Perhaps it is meant to be - but it definately is not!
I have unlocked 22 SkyDocks. It says I have unlocked 38.
A friend showed a count of 28 - I asked to exchange SkyDocks, he said he had only unlocked 2.
I think it is showing the number of times you have docked.