I appreciate this would be for iPad Air 2 owners only, but personally I think it would be useful in flight to have SD running on one half of the screen and another app running on the other side.

Yeah, to run in split screen is what I was thinking. I can see SD runs natively in iOS9 split screen already however in just a few moments of testing I can see there is some customisation required to makes sure it works properly / objects resize correctly. For example the pull down menus fill the entire side of the screen SD is operating on and doesn't show buttons to close / return to the map. Also if you resize the split screen those same pull down menu options all merge into each other making it hard to read/select.

Personally I think putting SD in split screen is a great idea - you could run any app you felt you needed along side (not that SD isn't perfect of course!!!???!!   ;-)  but I was for example think google maps (perhaps you want to be more precise of location) or say a more functionally rich notepad, or Windyty, or E6B calculator to allow you to do some in flight "what if's" planning. Options are endless I guess (as long as the other app also supports split screen - which will happen in time  as it is the "apple" way forward). (edit - the screen dump below doesn't do it justice due to the low resolution of images as they get uploaded to this forum. In real life - the clarity is gorgeous on an Air 2)

The answer to your original question is of course "it already does".

We are aware that there are nuances that need to be improved in a multitasking environment, such as the toolbar not properly resizing. We hope to address all of these by the end of the year, but we'll start much sooner than that. We certainly want SkyDemon to behave flawlessly in a multitasking iOS environment.

Great news! Thanks Tim.
Personally I think its a perfect reason for everyone who hasn't done, to go out and buy the iPad air 2.  :-)