I've noticed with the latest Android versions that the background running doesn't work anymore and we loose GPS when switched away.
I use another app called GPS Status, and when its closed or switches away, it appears in a window overlayed over other apps. you can move it around or close it, but it keeps running and updating its window.
Perhaps this would be possible with Fly is Fun and resolve the background issues.
Giving Fly is Fun the same functionality would be awesome. Allowing us to switch apps (or on tablets run other apps concurrently) and not loose the logging or GPS link when making phone calls or other such.