diff --git a/src/AIModel/AIAircraft.cxx b/src/AIModel/AIAircraft.cxx
index d0e319705..1c904b79b 100644
--- a/src/AIModel/AIAircraft.cxx
+++ b/src/AIModel/AIAircraft.cxx
@@ -52,11 +52,15 @@ using std::string;
 
 static string tempReg;
 
-FGAIAircraft::FGAIAircraft(FGAISchedule *ref) : FGAIBase(otAircraft) {
+FGAIAircraft::FGAIAircraft(FGAISchedule *ref) :
+     /* HOT must be disabled for AI Aircraft,
+      * otherwise traffic detection isn't working as expected.*/
+     FGAIBase(otAircraft, false) 
+{
     trafficRef = ref;
     if (trafficRef) {
         groundOffset = trafficRef->getGroundOffset();
-	setCallSign(trafficRef->getCallSign());
+        setCallSign(trafficRef->getCallSign());
     }
     else
         groundOffset = 0;
diff --git a/src/AIModel/AIBallistic.cxx b/src/AIModel/AIBallistic.cxx
index 69e090e3d..74b882821 100644
--- a/src/AIModel/AIBallistic.cxx
+++ b/src/AIModel/AIBallistic.cxx
@@ -40,7 +40,7 @@ const double FGAIBallistic::slugs_to_kgs = 14.5939029372;
 const double FGAIBallistic::slugs_to_lbs = 32.1740485564;
 
 FGAIBallistic::FGAIBallistic(object_type ot) :
-FGAIBase(ot),
+FGAIBase(ot, false),
 _height(0.0),
 _speed(0),
 _ht_agl_ft(0.0),
diff --git a/src/AIModel/AIBase.cxx b/src/AIModel/AIBase.cxx
index 33cb073cb..ac907c2e3 100644
--- a/src/AIModel/AIBase.cxx
+++ b/src/AIModel/AIBase.cxx
@@ -52,7 +52,7 @@ const double FGAIBase::lbs_to_slugs = 0.031080950172;   //conversion factor
 
 using namespace simgear;
 
-FGAIBase::FGAIBase(object_type ot) :
+FGAIBase::FGAIBase(object_type ot, bool enableHot) :
     _max_speed(300),
     _name(""),
     _parent(""),
@@ -121,6 +121,10 @@ FGAIBase::FGAIBase(object_type ot) :
     p = 1e5;
     a = 340;
     Mach = 0;
+
+    // explicitly disable HOT for (most) AI models
+    if (!enableHot)
+        aip.getSceneGraph()->setNodeMask(~SG_NODEMASK_TERRAIN_BIT);
 }
 
 FGAIBase::~FGAIBase() {
diff --git a/src/AIModel/AIBase.hxx b/src/AIModel/AIBase.hxx
index 2f8362331..61351adbb 100644
--- a/src/AIModel/AIBase.hxx
+++ b/src/AIModel/AIBase.hxx
@@ -52,7 +52,7 @@ public:
         otEscort, otMultiplayer,
         MAX_OBJECTS };	// Needs to be last!!!
 
-    FGAIBase(object_type ot);
+    FGAIBase(object_type ot, bool enableHot);
     virtual ~FGAIBase();
 
     virtual void readFromScenario(SGPropertyNode* scFileNode);
diff --git a/src/AIModel/AIMultiplayer.cxx b/src/AIModel/AIMultiplayer.cxx
index a9635c5f7..08f5afb40 100644
--- a/src/AIModel/AIMultiplayer.cxx
+++ b/src/AIModel/AIMultiplayer.cxx
@@ -29,18 +29,18 @@
 
 #include "AIMultiplayer.hxx"
 
-#include <simgear/scene/util/SGNodeMasks.hxx>
 
 // #define SG_DEBUG SG_ALERT
 
-FGAIMultiplayer::FGAIMultiplayer() : FGAIBase(otMultiplayer) {
+FGAIMultiplayer::FGAIMultiplayer() :
+   FGAIBase(otMultiplayer, false)
+{
    no_roll = false;
 
    mTimeOffsetSet = false;
    mAllowExtrapolation = true;
    mLagAdjustSystemSpeed = 10;
    mLastTimestamp = 0;
-   aip.getSceneGraph()->setNodeMask(~SG_NODEMASK_TERRAIN_BIT);
    lastUpdateTime = 0;
 
 } 
diff --git a/src/AIModel/AIShip.cxx b/src/AIModel/AIShip.cxx
index 9b6a04705..b5df3d145 100644
--- a/src/AIModel/AIShip.cxx
+++ b/src/AIModel/AIShip.cxx
@@ -42,7 +42,8 @@
 
 
 FGAIShip::FGAIShip(object_type ot) :
-FGAIBase(ot),
+// allow HOT to be enabled
+FGAIBase(ot, true),
 
 
 _waiting(false),
diff --git a/src/AIModel/AIStatic.cxx b/src/AIModel/AIStatic.cxx
index 83be7c8d6..5ac1f4ce3 100644
--- a/src/AIModel/AIStatic.cxx
+++ b/src/AIModel/AIStatic.cxx
@@ -33,7 +33,7 @@ using std::string;
 #include "AIStatic.hxx"
 
 
-FGAIStatic::FGAIStatic() : FGAIBase(otStatic) {
+FGAIStatic::FGAIStatic() : FGAIBase(otStatic, false) {
 }
 
 
diff --git a/src/AIModel/AIStorm.cxx b/src/AIModel/AIStorm.cxx
index fded8012d..a4241df46 100644
--- a/src/AIModel/AIStorm.cxx
+++ b/src/AIModel/AIStorm.cxx
@@ -35,7 +35,9 @@ using std::string;
 #include "AIStorm.hxx"
 
 
-FGAIStorm::FGAIStorm() : FGAIBase(otStorm) {
+FGAIStorm::FGAIStorm() :
+   FGAIBase(otStorm, false)
+{
    delay = 3.6;
    subflashes = 1;
    timer = 0.0;
diff --git a/src/AIModel/AIThermal.cxx b/src/AIModel/AIThermal.cxx
index 172d1e68a..f47ba2356 100644
--- a/src/AIModel/AIThermal.cxx
+++ b/src/AIModel/AIThermal.cxx
@@ -35,7 +35,9 @@ using std::string;
 #include "AIThermal.hxx"
 
 
-FGAIThermal::FGAIThermal() : FGAIBase(otThermal) {
+FGAIThermal::FGAIThermal() :
+   FGAIBase(otThermal, false)
+{
    max_strength = 6.0;
    diameter = 0.5;
    strength = factor = 0.0;
diff --git a/src/Airports/simple.cxx b/src/Airports/simple.cxx
index 9df1cb254..7354db28b 100644
--- a/src/Airports/simple.cxx
+++ b/src/Airports/simple.cxx
@@ -442,7 +442,7 @@ void FGAirport::processThreshold(SGPropertyNode* aThreshold)
   // first, let's identify the current runway
   string id(aThreshold->getStringValue("rwy"));
   if (!hasRunwayWithIdent(id)) {
-    SG_LOG(SG_GENERAL, SG_WARN, "FGAirport::processThreshold: "
+    SG_LOG(SG_GENERAL, SG_DEBUG, "FGAirport::processThreshold: "
       "found runway not defined in the global data:" << ident() << "/" << id);
     return;
   }
diff --git a/src/MultiPlayer/multiplaymgr.cxx b/src/MultiPlayer/multiplaymgr.cxx
index a8f862388..40a9c438a 100644
--- a/src/MultiPlayer/multiplaymgr.cxx
+++ b/src/MultiPlayer/multiplaymgr.cxx
@@ -1205,7 +1205,7 @@ FGMultiplayMgr::ProcessPosMsg(const FGMultiplayMgr::MsgBuf& Msg,
     else
     {
       // We failed to find the property. We'll try the next packet immediately.
-      SG_LOG(SG_NETWORK, SG_INFO, "FGMultiplayMgr::ProcessPosMsg - "
+      SG_LOG(SG_NETWORK, SG_DEBUG, "FGMultiplayMgr::ProcessPosMsg - "
              "message from " << MsgHdr->Callsign << " has unknown property id "
              << id); 
     }
diff --git a/src/Navaids/airways.cxx b/src/Navaids/airways.cxx
index 5bdbb2bee..8313f75b4 100644
--- a/src/Navaids/airways.cxx
+++ b/src/Navaids/airways.cxx
@@ -197,13 +197,13 @@ void Airway::Network::addEdge(Airway* aWay, const SGGeod& aStartPos,
   FGPositionedRef end = FGPositioned::findClosestWithIdent(aEndIdent, aEndPos);
     
   if (!start) {
-    SG_LOG(SG_GENERAL, SG_INFO, "unknown airways start pt: '" << aStartIdent << "'");
+    SG_LOG(SG_GENERAL, SG_DEBUG, "unknown airways start pt: '" << aStartIdent << "'");
     start = FGPositioned::createUserWaypoint(aStartIdent, aStartPos);
     return;
   }
   
   if (!end) {
-    SG_LOG(SG_GENERAL, SG_INFO, "unknown airways end pt: '" << aEndIdent << "'");
+    SG_LOG(SG_GENERAL, SG_DEBUG, "unknown airways end pt: '" << aEndIdent << "'");
     end = FGPositioned::createUserWaypoint(aEndIdent, aEndPos);
     return;
   }
diff --git a/src/Navaids/navdb.cxx b/src/Navaids/navdb.cxx
index 96d38c153..b1a813d61 100644
--- a/src/Navaids/navdb.cxx
+++ b/src/Navaids/navdb.cxx
@@ -297,12 +297,12 @@ FGRunway* getRunwayFromName(const std::string& aName)
   
   const FGAirport* apt = fgFindAirportID(parts[0]);
   if (!apt) {
-    SG_LOG(SG_GENERAL, SG_WARN, "navaid " << aName << " associated with bogus airport ID:" << parts[0]);
+    SG_LOG(SG_GENERAL, SG_DEBUG, "navaid " << aName << " associated with bogus airport ID:" << parts[0]);
     return NULL;
   }
   
   if (!apt->hasRunwayWithIdent(parts[1])) {
-    SG_LOG(SG_GENERAL, SG_WARN, "navaid " << aName << " associated with bogus runway ID:" << parts[1]);
+    SG_LOG(SG_GENERAL, SG_DEBUG, "navaid " << aName << " associated with bogus runway ID:" << parts[1]);
     return NULL;
   }
 
diff --git a/src/Navaids/navrecord.cxx b/src/Navaids/navrecord.cxx
index 5edc64ef1..8c01c6a10 100644
--- a/src/Navaids/navrecord.cxx
+++ b/src/Navaids/navrecord.cxx
@@ -61,7 +61,7 @@ FGNavRecord::FGNavRecord(Type aTy, const std::string& aIdent,
   // assign our own defaults, unless the range is not set for some
   // reason.
   if (range < 0.1) {
-    SG_LOG(SG_GENERAL, SG_WARN, "navaid " << ident() << " has no range set, using defaults");
+    SG_LOG(SG_GENERAL, SG_DEBUG, "navaid " << ident() << " has no range set, using defaults");
     switch (type()) {
     case NDB:
     case VOR:
diff --git a/src/Traffic/SchedFlight.cxx b/src/Traffic/SchedFlight.cxx
index 5575f6ee0..8b5b6ee68 100644
--- a/src/Traffic/SchedFlight.cxx
+++ b/src/Traffic/SchedFlight.cxx
@@ -269,13 +269,13 @@ bool FGScheduledFlight::initializeAirports()
   departurePort = FGAirport::findByIdent(depId);
   if(departurePort == NULL)
     {
-      SG_LOG( SG_GENERAL, SG_WARN, "Traffic manager could not find departure airport : " << depId);
+      SG_LOG( SG_GENERAL, SG_DEBUG, "Traffic manager could not find departure airport : " << depId);
       return false;
     }
   arrivalPort = FGAirport::findByIdent(arrId);
   if(arrivalPort == NULL)
     {
-      SG_LOG( SG_GENERAL, SG_WARN, "Traffic manager could not find arrival airport   : " << arrId);
+      SG_LOG( SG_GENERAL, SG_DEBUG, "Traffic manager could not find arrival airport   : " << arrId);
       return false;
     }