diff --git a/src/Autopilot/analogcomponent.hxx b/src/Autopilot/analogcomponent.hxx
index f5682baeb..d6bedf871 100644
--- a/src/Autopilot/analogcomponent.hxx
+++ b/src/Autopilot/analogcomponent.hxx
@@ -91,9 +91,9 @@ protected:
      * @param prop_root Property root for all relative paths
      * @return true if the node was handled, false otherwise.
      */
-    virtual bool configure( SGPropertyNode& cfg_node,
+    bool configure( SGPropertyNode& cfg_node,
                             const std::string& cfg_name,
-                            SGPropertyNode& prop_root );
+                            SGPropertyNode& prop_root ) override;
 
     /**
      * @brief clamp the given value if <min> and/or <max> inputs were given
@@ -107,7 +107,7 @@ protected:
     *        is disabled. Analog components feed back it's output value to the active
              input value if disabled and feedback-if-disabled is true
     */
-    virtual void disabled( double dt );
+     void disabled( double dt ) override;
 
     /**
      * @brief return the current double value of the output property
diff --git a/src/Autopilot/component.hxx b/src/Autopilot/component.hxx
index 4f3030976..80e1617be 100644
--- a/src/Autopilot/component.hxx
+++ b/src/Autopilot/component.hxx
@@ -20,12 +20,7 @@
 // along with this program; if not, write to the Free Software
 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 //
-#ifndef __COMPONENT_HXX
-#define __COMPONENT_HXX 1
-
-#ifdef HAVE_CONFIG_H
-#  include <config.h>
-#endif
+#pragma once
 
 #include <simgear/structure/subsystem_mgr.hxx>
 #include <simgear/props/propsfwd.hxx>
@@ -122,6 +117,5 @@ public:
     bool isPropertyEnabled();
 };
 
-}
+} // of namespace FGXMLAutopilot
 
-#endif // COMPONENT_HXX
diff --git a/src/Autopilot/digitalfilter.hxx b/src/Autopilot/digitalfilter.hxx
index 7c923ba02..7be809497 100644
--- a/src/Autopilot/digitalfilter.hxx
+++ b/src/Autopilot/digitalfilter.hxx
@@ -20,12 +20,7 @@
 // along with this program; if not, write to the Free Software
 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 //
-#ifndef __DIGITALFILTER_HXX
-#define __DIGITALFILTER_HXX 1
-
-#ifdef HAVE_CONFIG_H
-#  include <config.h>
-#endif
+#pragma once
 
 #include "analogcomponent.hxx"
 
@@ -47,12 +42,12 @@ private:
     };
 
 protected:
-    virtual bool configure( SGPropertyNode& cfg_node,
+    bool configure( SGPropertyNode& cfg_node,
                             const std::string& cfg_name,
-                            SGPropertyNode& prop_root );
-    virtual void update( bool firstTime, double dt);
+                            SGPropertyNode& prop_root ) override;
+    void update( bool firstTime, double dt) override;
 
-    InitializeTo _initializeTo;
+    InitializeTo _initializeTo = INITIALIZE_INPUT;
 
 public:
     DigitalFilter();
@@ -66,4 +61,4 @@ public:
 };
 
 } // namespace FGXMLAutopilot
-#endif
+
diff --git a/src/Autopilot/pidcontroller.hxx b/src/Autopilot/pidcontroller.hxx
index 354928e2d..450b447ae 100644
--- a/src/Autopilot/pidcontroller.hxx
+++ b/src/Autopilot/pidcontroller.hxx
@@ -86,7 +86,7 @@ public:
     // Subsystem identification.
     static const char* staticSubsystemClassId() { return "pid-controller"; }
 
-    void update( bool firstTime, double dt );
+    void update( bool firstTime, double dt ) override;
 };
 
 }