Humanity's first forays into air travel are a great example of the different approaches of biomimetics: using structures straight from nature vs. applying core principles of the functions. A lot of nature's perfected mechanisms don't translate well into people technology. When that happens we have to look deeper and examine the functional attributes before we can try to replicate a process.
Gliding was something we could master by straight up copying the parts of certain mammals. We now manufacture gliding suits designed like the tissue of sugar gliders and flying squirrels: