A verb in the Gnomish Lexicon of the 1910s glossed “to fly”, based on G. duil “flight” (GL/31).
Gnomish
gwil-
verb. to sail, float, fly
duila-
verb. to fly
There are more words but they are from Tolkien's earlier conceptional periods. Tolkien likely changed these words as he evolved the aesthetics and completeness of the languages. You may even find languages that Tolkien later rejected. Do not mix words from different time periods unless you are familiar with the phonetic developments.
Below: Tolkien's Late Period (1950–1973). These are from Tolkien's late conceptual period — his most settled forms of the languages. Prefer these over the earlier ones above when composing new text.
A verb appearing in the Gnomish Lexicon of the 1910s as G. gwil- “sail, float, fly” derived from ᴱ√gu̯il (GL/45). It was cognate to ᴱQ. vil- or ’wili- “sail, fly, float” (QL/104).
Neo-Sindarin: Since [ᴹQ.] vil- or wil- “fly” survived in Tolkien’s later writings (Ety/WIL), I would retain ᴺS. gwil- as well, but only for the sense “to fly”. For “float” and “sail” I would use other verbs like ᴺS. loda- “float” [N. lhoda-] and ᴺS. renia- “sail” [N. rhenia-].