If your are flying FPV you need to still have visual contact with the aircraft. If you are using goggles then you need a spotter. The FAA regulations require us to "see and avoid" any full scale aircraft at all times. Full scale aircraft have the right of way at all times. To be able to see your aircraft 1/2 mile away it would have to be very large. I start having have trouble orienting my Giant planes (+100" wingspan) if it get that far out.