Two possible points of interest about the
Eagles in all of the three decisive confrontations in the three
books of the legendarium, end of the
War of Wrath,
Battle of Five Armies, and the confrontation at the
Black Gate of
Mordor:
1. The Eagles are always late arrivals at the scene of battle, and while they do even things out somewhat, sometimes more, sometimes less ...
2. They are never the
decisive intervention.
In the Sil,
Eärendil takes out
Ancalagon the Black and trashes
Thangorodrim in the process;
In TH, it is
Beorn in (huge) bear's form who turns the tide, crumpling
Bolg like tinfoil in the Process (
Azog of course has been dead for 142 years by now); get three seconds in the film ...
In LoTR, the confrontation at the Black Gate was a diversion, but definitely a decisive diversion;
Gollum causing
the One Ring (with himself) to fall into the Cracks of Doom settles things.