In Canada uncontrolled airspace are the areas not in an aerodrome and goes up to 1,500 feet (?), I forget the exact height, that's where radio controlled planes, hangliders, ultra-light aircraft, hot air balloons can go without needing a pilot's license or special permit.<p>If there was some device floating or flying there but not in controlled airspace or a danger to other aircraft it is perfectly legal for it to be there.