When I first got my P2V over a year ago I got a Flytrex Core 1 for it. It showed my longest flight at just over 1000 feet (distance). I'm not sure if it was accurate or not, but it scared the crap out of me because it was but a dot near the horizon. I live in Nevada so there's lots of open space unencumbered with wires, buildings, or even trees in most cases. Still, barely being able to see it was heart stopping. Now, with only a couple firmware upgrades (controller 3.06, Android app 1.0.52) I've lost all kinds of distance. I feel lucky if I get over 400 feet. BUT, I can see it and tell which way it's going - so life is good. I get all the video I want, and my stills are great. Wish I had a gimbal, but that can be added someday.
Not sure why you'd want over a mile of distance, and like dirkclod said, if you get too far out, you won't get back from lack of power. Besides, I think some of the latest software upgrades calculate how much 'juice' you have left and automatically starts a RTH function. I could be wrong on that - because I haven't bothered to get all the upgrades in firm / software.
I had two batteries when it was new, but due to my lack of storing them properly (should have been about a 50% charge instead of full charge like I did with both) I now have only one that seems to be fairly good. The other barely charges, and flying consists of taking off - and almost immediately hearing the "DEFCON ONE" alarm. Drat! So a new battery is in order. I'm wondering if that could have something to do with my distance problems. :?: