I think the only ones that DO fly are Mallards and Muscovy ducks, and those fancy ones, wood, mandarin etc... I might be wrong... My Khaki campbells dont, my pekin doesn't, my mallards DO, my swedish don't...
My Khaki drake flew all over the place, low and far, but always returned. He would fly up to 6 acres away to the pond! My call ducks took flight within an hour of me bringing them home, they flew off and never returned!
My Pekins have never even tried...lol..they can;t even get out of their own way!
When I got my call ducks I put them in a pen with a pool for about a month. Now I can let them out so I can clean the pen or just for fun when I am out with them and they will herd back in. To many predators to let them roam free all the time.
They can fly but will come back once they know where they belong. I also have a Khaki Campbell and a Blue Swedish. They flap and get off the ground but are happy to go back to a safe secure area for easy FOOD!