Turner and colleagues interpreted the presence of feathers on Velociraptor as evidence against the idea that the larger, flightless maniraptorans lost their feathers secondarily due to larger body size. Furthermore, they noted that quill knobs are almost never found in flightless bird species today, and that their presence in Velociraptor (presumed to have been flightless due to its relatively large size and short forelimbs) is evidence that the ancestors of dromaeosaurids could fly, making Velociraptor and other large members of this family secondarily flightless, though it is possible the large wing feathers inferred in the ancestors of Velociraptor had a purpose other than flight. The feathers of the flightless Velociraptor may have been used for display, for covering their nests while brooding, or for added speed and thrust when running up inclined slopes.
where did u learn this? also, it did
Among other places where I learned the evidence I presented, was in the paper describing the dromaeosaurid Zhenyuanlong suni (slightly smaller than Velociraptor), which was fully feathered as the fossil clearly shows: www.ncbi.nlm.nih.gov/pmc/artic… . This creature was completely flightless, and yet it still had feathers all over its body, including what appears to be a tail fan. Dakotaraptor too shows evidence of feathers in the form of quill knobs. Admitted, that is indirect evidence, but as modern flightless birds are feathered and do not possess quill knobs, it presents what is essentially clear and established; dromaeosaurids were fully feathered.