My whole deal when I do accents or dialects is I gotta fool the locals. If I fool the locals then I've done my job.
If I'm going to fly for more than twenty feet it's generally a good idea to get a stunt guy.
When you think of a movie, most people imagine a two hour finished, polished product. But to get to that two hour product, it can take hundreds or thousands of people many months of full time work.