In a German two-piece documentary History of fantasy Herman Weigel, one of the screenwriters of Neverending Story, talks about his work on the film. In the 15th minute of the second episode he says:
Falkor is based on Chinese dragons.
He doesn't specify if he means that they based the film version of Falkor on Eastern-type dragons or that the book version is already based on them.
Regarding the book I didn't find any sources citing Michael Ende himself. However it should be noted that Falkor's name, appeareance and behaviour contains many hints regarding the author's inspirations. This has been summarised on this page:
Falkor’s name in the original German novel is “Fuchur” which was apparently derived from the Japanese word fukuryū. Fuku meaning “happiness, luck” and Ryū meaning “dragon”. And so we have Falkor being the luckdragon in Fantastica. But fukuryū has been mentioned as meaning “hidden dragon” or “crouching dragon” as well.
(...) aside from the meaning of his name, he also shares physical attributes with Japanese dragons. Falkor is long, slender, serpentine, bearded, and a combination of various animals, and has 3 claws on each foot. Where he differs, at least in the film’s depiction, is that he’s covered in fur and has a canine head. Mostly to make him more appealing to the audience. In the book, however, Falkor’s body is covered in pink and white scales and he has an impressive mane around a lion-like head. Falkor was considered pure, warm, and a creature of air, which was why he didn’t need wings in order to fly. He could also spew forth a blue flame when needed.