The original manuscript reads “flying fiery serpents” (with fiery spelled as firey). In copying from 𝓞 into 𝓟, Oliver Cowdery switched the order of the two modifiers flying and fiery. The text now conforms to the phrase “fiery flying serpent” that is found in Isaiah in the King James Bible:
The first of these is quoted in the Book of Mormon:
In all of these, the order is “fiery flying serpent”.
But the use of “flying fiery serpents” in 1 Nephi 17:41 refers to the “fiery serpents” that attacked the Israelites while they wandered in the wilderness:
In these passages from the Torah, the word flying does not occur, so its use in 1 Nephi 17:41 seems to have been influenced by the Isaiah passages. Probably Nephi himself is responsible for the intrusive word flying, especially given his frequently expressed preference for citing from the book of Isaiah (see 2 Nephi 6:4, 2 Nephi 11:2, and 2 Nephi 25:5). We should not be surprised that the language of Isaiah might influence Nephi’s own phraseology.
In the two Isaiah passages as well as the one in Numbers 21:8, there is a single Hebrew word for ‘fiery serpent’, namely s𝓞 fflarfflaf, which is interpreted as being derived from a verb stem originally meaning ‘to burn’ (see under s-r-p in Francis Brown, S. R. Driver, and Charles A. Briggs, A Hebrew and English Lexicon of the Old Testament [Oxford: Clarendon Press, 1952]). In the two other passages (Numbers 21:6 and Deuteronomy 8:15), the Hebrew word for ‘serpent’, nffla‚hffla¸s, occurs with the modifying s𝓞 fflarfflaf (literally, ‘burning serpent’). Essentially, the reference in all these cases is to a poisonous snake (whose bite “burns”). Thus, in a literal translation of the Hebrew in any of these five passages, the words fiery and serpent should occur together. In the Isaiah passages, where the word for flying is added, the literal translation would thus be “flying fiery serpent”, which is the word order found in the original manuscript for 1 Nephi 17:41. But in 2 Nephi 24:29 (which quotes Isaiah 14:29 from the King James Bible), the Book of Mormon text follows the King James word order, namely “fiery flying serpent”, while the Hebrew there supports the original reading in 1 Nephi 17:41, where fiery and serpent occur together and flying precedes fiery.
Summary: Restore in 1 Nephi 17:41 “flying fiery serpents”, the reading of the original manuscript; this word order follows the Hebrew construction, while in 2 Nephi 24:29 the word order found in the King James version of Isaiah 14:29 is maintained (as “fiery flying serpent”).