When pointing to an allied fleet on the galaxy map, did you noticed that sometimes you get detailed fleet informations, and sometimes not?
Here's what it looks like:

On this screenshot you can see the number of ships in the fleet and the time to destination; precious informations when launching synchronised operations between allies!
So why do you see these informations for some fleets, and not for others?
Because only the players whose informations you see have added you among their friends.
Every player can manage his list of friends, and by the way, choose with which other players share his fleets informations:
ucp.php?i=177So if you want to see the fleet details of an ally, maybe you can start by adding him as your friend so he can see yours

And then, you can send him a private message on the forum to remind him to add you as his friend too!
Maybe you're asking:
Why don't we see by default the fleet information of every allies, without having to manage this boring "friend" thing???
Then remember how easy it was to register an account on the game and enlist a character... Are you sure that you can trust all of your so-called "allies" ?

So I preferred to let everyone choose who he wants to trust!
And remember:
When a character dies, the player can re-enlist a new one. And then he can choose to enlist his new character on the other side than his previous character!
So maybe you should sometimes check your "friends" list if you don't want to leak informations to the enemy
