I just tried it for you, the MFI controller works with this app, and is fully configurable under the controls menu option in the setting menu.
Axis can be assigned to roll, pitch, yaw, throttle (and can be reversed with a check box)
Buttons can be assigned as well.
It lists available devices in settings as iOS gamepad (8 axes, 10 buttons) and Accelerometer (2 axes, 0 buttons.)
The app also references keyboard controls. Using a bluetooth keyboard I was UNABLE to get any keyboard key presses to register, even in the setup page.
I am not sure if it's just a lazy port issue, or if they intended to support iOS Keyboard controls, but it is currently broken.
[doublepost=1516649002][/doublepost]FYI, found this web page thought the app:
https://community.infinite-flight.com/t/joystick-support-in-infinite-flight/13715