var vtn_player_type = "vp";var ven_video_key="NjExMjQwfHwxNDcxfHwwfHx8fHx8";var ven_width="660";var ven_height="409";The creators of the 'AirDog' drone claim it will revolutionise the filming of extreme sports as the device follows its owner wherever he or she goes.