var lineSymbol = {
                          path: google.maps.SymbolPath.FORWARD_CLOSED_ARROW
                      };

                      var flightPath = new google.maps.Polyline({
                                  path: flightPathCoordinates,
                                  geodesic: true,
                                  strokeColor: '#5443b2',
                                  strokeOpacity: 0.8,
                                  strokeWeight: 4,
                                  icons: [{
                                      icon: lineSymbol,
                                      offset: '100%'
                                  }],