leaflet - clear overlay layer and put new polyline and markers on same layer -

i've been pulling hair out day trying figure 1 out. i'm writing thought simple leaflet app track aircraft movement historical gps plot data. idea able pick period of time display, display aircraft movement on map start , endpoints , polyline showing path aircraft took. want polyline own layer can turn on , off.

first time through, works great. different polylines each flights tracked wanted. however, when want pick different aircraft on same or different days, can't clear off old ploylines , display new ones. i've tried deleting objects out of layergroup, clear layergroup , else i've found try end result can clear out old polylines, can never new ones display.

here code creates map , layers:

var basemaps = {          "default": maplayer,              "faa": faalayer,          "satellite": satlayer,          "hybrid": hybridlayer       };    var polylayer =  l.layergroup([]);   var overlaymaps = {          "track": polylayer       };     var map = l.map('leafletmap', {     center: [33.559768, -117.728416],     zoom: 8,     layers: [maplayer, polylayer ]   });    var layercontrols = {          "map": maplayer,          "track": polylayer        };    l.map.include({     'clearlayers': function() {       this.eachlayer(function(layer) {             if (!layer._tiles) {           this.removelayer(layer);         }       }, this);     }   });    l.control.layers(basemaps, overlaymaps ).addto(map);   new controller(map,polylayer).init(); 

for real time tracking, position updates every 2 minutes, move icon on map previous position new position, , plot polyline old lat/long new lat/long. keeping array of plotted positions can remove plane icon previous position , move new one. here code plots position updates:

  /**    * if first tracking record, add array.    * if not, need remove marker previous position, add    * polyline previous position current position, set    * marker @ new position.    */   if ( trackingrecordlen === 0 ) {      // add new marker array , update length      trackingrecord.push( startmark );      trackingrecordlen++;      //markerlayer.push( mark );      //markerlayer.addlayer(mark);      markerlayer.push( startmark );      l.layergroup(markerlayer).addto(map);   }   else {       // first, remove marker @ previous position if not first 1      if (trackingrecordlen > 1 )          map.removelayer( trackingrecord[ trackingrecordlen-1 ] );       // add new marker array      trackingrecord.push( cessnamark );      trackingrecordlen++;       trackinglayergroup.push( cessnamark );      markerlayer.push( cessnamark );      //l.layergroup(layergroup).addto(map);       // add polyline last position new position      var prevlatlng = l.latlng( trackingrecord[ trackingrecordlen-2 ].getlatlng() );      var newlatlng = l.latlng ( trackingrecord[ trackingrecordlen-1 ].getlatlng() );      var polyline = l.polyline([prevlatlng, newlatlng], {color: linecolor }).addto(polylayer);    } 

when want track new group of aircraft data, following clear out old polylines:

polylayer.clearlayers(); 

works clear out old polylines, when code above executed, no new polylines plotted. doing wrong?

thanks help.