[Voronwe]

The Eagles certainly seem rather mysterious beasts. They either turn up when escape by other means appears impossible, or at the crucial moment of a finely balenced battle.

It is possible that the Eagles were a way in which the Lords of the West influenced events in Middle Earth when a little help was needed. For example, the consequences of Gandalf not being rescued from Orthanc would quite likely have been disasterous.

However, if the eagles were under the control of the Lords of the West, they would almost certainly have not been prepared to do something as direct as carry the Ring to the fire. The Ring 'belonged to Middle Earth' - it was something for the free peoples to deal with on their own.

From a pratical standpoint, it would probably have been a very tiring journey for both Frodo and the Eagle carrying him. I don't recall any instances of people actually riding on Eagle's backs - they always seem to have been carried by the arms. All the recorded 'eagle carryings' were over relatively short distances compared to the flight from (say) Rivendell to Mordor.

Finally, even if an eagle had succeeded in carrying Frodo and the Ring all the way to Mount Doom, Frodo would not have been able to throw it into the Fire, and the whole quest would be vain. Frodo would quickly have been spotted by Sauron, and the ring would have been taken from him and returned to Sauron.

It was Galadriel who sent Gwaihir to look for Gandalf when he was carried (newly reincarnated) from Zirak-Zigal.

-Voronwe