With some recent iPads it is possible to get some (but not all) iPad apps to open in Slide Over mode over iFly, so that both apps are visible and running on the display at the same time. This is undocumented (and perhaps unwanted by AP) and many apps won't do it. For example, here's the Messages app open that way on my iPad Mini 6:
Slide Over windows will slide sideways across the screen to reveal the portion of the full screen app (iFly here) that it has been covering up. You can also change it to full screen (which changes away from iFly without closing it, and you then can change back to it when you're finished. You can also close the slideover app if you wish.
You can also slide the Slide Over app all the way to a vertical side of the screen, so that it disappears except for a small tab in the middle of the vertical edge. Then when you need it you can drag it back onto the visible portion of the screen.
To work this Slide Over trick, run iFly, then slide up the taskbar slightly at the bottom of the screen and drag Messages (or some other app that appears there) up onto the iFly screen. I've used it in flight several times when trying to join up with other airplanes by contacting the pilots with text messages. IFly goes right on working.
Some apps open in Slide Over with iFly, some do not. You just have to try it and see.