It doesn't matter how slow I made it or how gradual of a climb, they still can't keep up.
I've set it so slow I thought the AI planes would fall out of the sky, they still can't keep up.
The mission I created is for B-17s climbing at normal power. The player controlled plane worked perfectly on auto climb and auto level.
That's when I started to slow them down, but no luck.
I guess I just don't now how to use the ME.
I've updated to 2.22 so I'll have to wait for the new ME to do more experimenting.