Eagle of the Misty Mountains.
Vassal of Gwaihir and Landroval.
In Sindarin, the root word 'menel' means heaven; the suffix 'dor' means land (as opposed to sea).
Meneldor was one of three Eagles to help rescue Frodo and Sam from Mount Doom after the One Ring was destroyed.
T. A. 3019 (25/03) As Sauron's realm ended and Mount Doom quaked and convulsed, Gandalf sought the Eagles' help to rescue Frodo and Sam. He told Gwaihir to "come, and let your brother [Landroval] go with us, and some other of your folk who is most swift! For we have need of speed greater than any wind, outmatching the wings of the Nazgûl."
From this, it seems that Gwaihir chose the third eagle for the rescue mission. That third eagle was "Meneldor young and swift." Meneldor must have been one of the swiftest Eagles of the Misty Mountains. Based on Gandalf's stated needs, he was also apparently capable of flying faster than the Nazgûl. Such speed would be critical if the Nazgûl attacked during the rescue mission to Mount Doom.
As Orodruin reeled and fire "belched from its riven summit," the two Hobbits escaped from Sammath Naur and made their way down the mountain road only to be trapped by "rivers of fire" as Mount Doom exploded. "They had reached a low ashen hill piled at the Mountain's foot; but from it there was no more escape." "Side by side they lay; and down swept Gwaihir, and down came Landroval and Meneldor the swift; and in a dream, not knowing what fate had befallen them, the wanderers were lifted up and borne far away out of the darkness and the fire."
T. A. 3091 (08/04) When Sam finally awoke after the rescue, he found himself outside "lying on some soft bed, but over him gently swayed wide beechen boughs..." with Gandalf at his side. This beech-grove was near the Field of Cormallen in the land of Ithilien. Since they were wary of men, it is not surprising that the Eagles carried their 'cargo' to an unpopulated, yet strategic, location such as this.
To reach this beech-grove, the Eagles carried Gandalf, Frodo, and Sam some 75 miles (using distance scales from 'The Atlas of Middle Earth') directly west from Mount Doom, over Ephel Dúath and across the forest west of this mountain range, to the eastern side of the River Anduin near Cair Andros. It is not told how much time elapsed during this flight. Fourteen days had elapsed from the destruction of the One Ring to the day when Sam awoke in the beech-grove and asked Gandalf what day it was. (Sam learned that it was the "fourteenth of the New Year..." Gandalf explained that the "New Year will always now begin upon the twenty-fifth of March when Sauron fell, and when you were brought out of the fire to the King.")
It is almost certain that the Eagles' journey from Mount Doom to the beech-grove did not take fourteen days. Frodo and Sam likely needed many days to recouperate from their arduous quest. At the end of the day that they were honored in the Field of Cormallen, Gandalf told the Hobbits that "the King" (Aragorn II) "sent you into the sweet forgetfulness of sleep. And though you have indeed slept long and blessed, still it is now time to sleep again."
If the Eagles flew non-stop from Oroduin to the beech-grove, it seems likely that crossing this 75 mile distance took hours, rather than days, to complete. Supporting this assumption is the fact that scientists have determined, with the help of satellite telemetry, that some modern-day eagles are able to sustain speeds up 65 miles per hour and can cover up to 200 miles in a single day. Certainly the Great Eagles of the Misty Mountains could achieve at least as much.
There is no further mention of Meneldor after this tale.