Stack callsign below altitude

src/FlightMap/MapItems/VehicleMapItem.qml

@@ -57,6 +57,7 @@ MapQuickItem {
         }
 
         QGCMapLabel {
+            id:                         vehicleLabel
             anchors.top:                parent.bottom
             anchors.horizontalCenter:   parent.horizontalCenter
             map:                        _map
@@ -66,10 +67,21 @@ MapQuickItem {
 
             property string vehicleLabelText: visible ?
                                                   (_adsbVehicle ?
-                                                       callsign + " " + QGroundControl.metersToAppSettingsDistanceUnits(altitude).toFixed(0) + " " + QGroundControl.appSettingsDistanceUnitsString :
+                                                       QGroundControl.metersToAppSettingsDistanceUnits(altitude).toFixed(0) + " " + QGroundControl.appSettingsDistanceUnitsString :
                                                        (_multiVehicle ? qsTr("Vehicle %1").arg(vehicle.id) : "")) :
                                                   ""
 
         }
+
+        QGCMapLabel {
+            anchors.top:                vehicleLabel.bottom
+            anchors.horizontalCenter:   parent.horizontalCenter
+            map:                        _map
+            text:                       vehicleLabelText
+            font.pointSize:             ScreenTools.smallFontPointSize
+            visible:                    _adsbVehicle ? !isNaN(altitude) : _multiVehicle
+
+            property string vehicleLabelText: visible && _adsbVehicle ? callsign : ""
+        }
     }
 }