Identifying flight feathers

Q:  I can't really figure out the difference between a flight feather and a body feather - I know that a flight feather has asymmetric vanes but it looks like
body feathers are asymmetrical as well.

A: Do you remember seeing these feathers in the flight lab?  One was clearly much more asymmetrical than the other.  I suggest you look at the 4th picture down on this page (http://www.earthlife.net/birds/feathers.html) which shows a flight feather(labeled remige) next to a body feather (labeled retrice).  The body feather may be slightly asymmetrical, but in most cases there is no doubt about the flight feather's asymmetry.