Gaia works fine in airplane mode as a GPS....whether you are in cell range or not.  If you want to use maps and aerial photos for an area where you are out of cell coverage, just download them off WIFI or cell coverage ahead of time and save them......easy or I couldn't do it.  Gaia does not show land ownership.  It works great in BC, Canada. My favorite of the 13 map/photo options Gaia came with is "world imagery and roads" so I assume it works all over the world, but I haven't looked more than 3000 km from home so can't personally verify this.  
For $20 if you already have an iPhone or iPad, just buy the Gaia app.  You can put it on up to 5 devices.  Seems like a no brainer to me versus a $300-$600 GPS with map chips that cost $150 when we bought ours a few years ago.  The iPhone 5S with Gaia I use blows away the Garmin Oregon 450T GPS that I had and broke the screen on.  Good luck with it!