I see this question arise from time to time: Why doesn't Gandalf think about sending the eagles - by themselves or with Frodo - to Orodruin instead of attempting such a perilous and most likely doomed journey?
Aside from the narrative standpoint - what would the book be about? - I think there're some fairly practical reasons.
First, eagles are allies, not servants, you have to obtain their permission...
Second, Sauron has a lot of beasts at his command, including flying monsters, even before the Nazgul air force (and there's Saruman to consider, too). Eagles, especially with the Ring can be spotted and might not be able to defend themselves. Besides, they can't fly non stop from Rivendell to Mount Doom, they have to rest and make themselves more vulnerable.
Finally, Mordor is Sauron's land, where his power is at the strongest. He might have overlooked small creatures like hobbits but he must have taken into account eagles, traditional - and powerful - enemies of the dark lords. The eagles didn't dare flying over Mordor until he was gone.
Aside from the narrative standpoint - what would the book be about? - I think there're some fairly practical reasons.
First, eagles are allies, not servants, you have to obtain their permission...
Second, Sauron has a lot of beasts at his command, including flying monsters, even before the Nazgul air force (and there's Saruman to consider, too). Eagles, especially with the Ring can be spotted and might not be able to defend themselves. Besides, they can't fly non stop from Rivendell to Mount Doom, they have to rest and make themselves more vulnerable.
Finally, Mordor is Sauron's land, where his power is at the strongest. He might have overlooked small creatures like hobbits but he must have taken into account eagles, traditional - and powerful - enemies of the dark lords. The eagles didn't dare flying over Mordor until he was gone.