There are notes of caution be given:
“Four-Winged Dinosaurs Found in China, Experts Announce
Hillary Mayell
for National Geographic News
January 22, 2003
“That’s certainly a possibility,(gliding to flying) and very plausible, but interpreting function from a fossil is highly speculative,” he said. “There’s just a lot we aren’t going to know.”
Mark Norell, chairman of the division of paleontology at the American Museum of Natural History, concurs. “I think you have to be really cautious about inferring biomechanical properties from fossils. However, what these fossils do tell us is that there are some really strange creatures out there, unlike anything around today.
“This shows that people really have to change their conceptions of what dinosaurs are all about,” he said. “They’re incredibly varied, incredibly diverse, and include everything from small feathered creatures to the large dinosaurs people are most familiar with.”
A thoughtful statement there. Some bio-mechanics can be discerned from range of motion skeletal constraints but beyond that it’s a bit of fancy. The caution is well placed.