When I run my own (first) app in the simulator it is the correct size for iPhone 4s but if I change the simulator to iPhone 6 I get black bars at the top and bottom. Trying this with the Eddie’s Electronics sample app does the same thing. I was hoping that Parent in the auto layout would automatically be full screen for each device - am I missing something simple in my understanding or expectation?
That means you dont have the require launch images for the iPhone 6
Search the forum for “black bars” 
Slapped my head - the need to do that is so annoyingly not obvious, but I guess searching for ‘black bars’ is. Thanks Norman.
Yeah its not obvious how iOS figures out what you device is optimized for
But that turns out to be the trick
While the searching on the forums leaves some room to be improved often searching first will often find something useful
It saves you the trouble of even asking
Ahhhhh!!! This has been plaguing me forever!
Thanks guys!