[MarchHare]

Spoiler!

You act as if these Eagles are commanded by Gandalf. They are a Valar race, they are in their minds superior to everyone around them. The only reason Gandalf is able to call upon these favours is because he is of the same stature as them and the Eagle Lord owes him small debts along the plot lines. (There is a really big one I am not sure if I can spoil or not if you haven't read the book that explains any co operation they will find in this novel.)

Re your spoiler:

Spoiler!

Again, none of that is communicated to an audience that is only familiar with the films, not the books (like my wife, for example). The only thing film viewers see is Gandalf whispering a command to a moth and then a few minutes later the eagles show up to save the day. It very much looks like Gandalf is using his magic to make the eagles do his bidding.