[Sardy]

Not sure that I agree. Sauron's downfall was that, in his lust for power, he never in his wildest imagination considered that anyone might try to destroy the Ring. THAT was the strength of Gandalf's plan, not it's "foolishness."

That said, if Frodo (or Gandalf, or Aragorn, or Glorfindel) were to attempt to ride an Eagle to Mt. Doom, they would have had a very good (better that Frodo walking it there) chance. I still contend that the Ringwraiths were currently out-of-commission. Sauron would never have blocked passage to Mt. Doom (either with orcs or boulders) because he would have assumed that whoever was riding the Eagle was riding in to challenge him mano-e-mano using his own ring against him. Sauron would've been shocked and dismayed as the Eagle swooped right on past his tower and on to the Crack of Doom, leaving the Dark Lord with no time to do anything but watch as the Ring's inevitable unmaking proceeded.