diff --git a/src/blackcore/simulatorcommon.cpp b/src/blackcore/simulatorcommon.cpp
index bce057287..315753d33 100644
--- a/src/blackcore/simulatorcommon.cpp
+++ b/src/blackcore/simulatorcommon.cpp
@@ -162,7 +162,7 @@ namespace BlackCore
         const qint64 time = QDateTime::currentMSecsSinceEpoch();
         IInterpolator::InterpolationStatus interpolationStatus;
         const CAircraftSituation as(m_interpolator->getInterpolatedSituation(callsign, time, aircraft.isVtol(), interpolationStatus));
-        if (interpolationStatus.interpolationSucceeded)
+        if (interpolationStatus.didInterpolationSucceed())
         {
             aircraft.setSituation(as);
             return true;
diff --git a/src/blackmisc/interpolator.cpp b/src/blackmisc/interpolator.cpp
index e45b75534..38df1cfd9 100644
--- a/src/blackmisc/interpolator.cpp
+++ b/src/blackmisc/interpolator.cpp
@@ -40,7 +40,7 @@ namespace BlackMisc
     CAircraftPartsList IInterpolator::getPartsBeforeTime(const CAircraftPartsList &parts, qint64 cutoffTime, BlackMisc::IInterpolator::PartsStatus &partsStatus) const
     {
         partsStatus.reset();
-        partsStatus.supportsParts = true;
+        partsStatus.setSupportsParts(true);
 
         if (cutoffTime < 0) { return parts; }
         return parts.findBefore(cutoffTime);
@@ -51,8 +51,8 @@ namespace BlackMisc
         Q_ASSERT_X(!callsign.isEmpty(), Q_FUNC_INFO, "empty callsign");
         partsStatus.reset();
 
-        partsStatus.supportsParts = this->isRemoteAircraftSupportingParts(callsign);
-        if (!partsStatus.supportsParts) { return {}; }
+        partsStatus.setSupportsParts(this->isRemoteAircraftSupportingParts(callsign));
+        if (!partsStatus.isSupportingParts()) { return {}; }
         return this->remoteAircraftParts(callsign, cutoffTime);
     }
 
@@ -70,22 +70,22 @@ namespace BlackMisc
 
     bool IInterpolator::InterpolationStatus::allTrue() const
     {
-        return interpolationSucceeded && changedPosition;
+        return m_interpolationSucceeded && m_changedPosition;
     }
 
     void IInterpolator::InterpolationStatus::reset()
     {
-        changedPosition = false;
-        interpolationSucceeded = false;
+        m_changedPosition = false;
+        m_interpolationSucceeded = false;
     }
 
     bool IInterpolator::PartsStatus::allTrue() const
     {
-        return supportsParts;
+        return m_supportsParts;
     }
 
     void IInterpolator::PartsStatus::reset()
     {
-        supportsParts = false;
+        m_supportsParts = false;
     }
 } // namespace
diff --git a/src/blackmisc/interpolator.h b/src/blackmisc/interpolator.h
index f0a5686af..e2eb1cb0a 100644
--- a/src/blackmisc/interpolator.h
+++ b/src/blackmisc/interpolator.h
@@ -43,9 +43,22 @@ namespace BlackMisc
         //! Status of interpolation
         struct BLACKMISC_EXPORT InterpolationStatus
         {
+        private:
+            bool m_changedPosition = false;        //!< position was changed
+            bool m_interpolationSucceeded = false; //!< interpolation succeeded (means enough values, etc.)
+
         public:
-            bool changedPosition = false;        //!< position was changed
-            bool interpolationSucceeded = false; //!< interpolation succeeded (means enough values, etc.)
+            //! Did interpolation succeed?
+            bool didInterpolationSucceed() const { return m_interpolationSucceeded; }
+
+            //! Set succeeded
+            void setInterpolationSucceeded(bool succeeded) { m_interpolationSucceeded = succeeded; }
+
+            //! Changed position?
+            bool hasChangedPosition() const { return m_changedPosition; }
+
+            //! Set as changed
+            void setChangedPosition(bool changed) { m_changedPosition = changed; }
 
             //! all OK
             bool allTrue() const;
@@ -57,11 +70,19 @@ namespace BlackMisc
         //! Status regarding parts
         struct BLACKMISC_EXPORT PartsStatus
         {
-            bool supportsParts = false;   //!< supports parts for given callsign
+        private:
+            bool m_supportsParts = false;   //!< supports parts for given callsign
 
+        public:
             //! all OK
             bool allTrue() const;
 
+            //! Supporting parts
+            bool isSupportingParts() const { return m_supportsParts; }
+
+            //! Set support flag
+            void setSupportsParts(bool supports) { m_supportsParts = supports; }
+
             //! Reset to default values
             void reset();
         };
diff --git a/src/blackmisc/interpolatorlinear.cpp b/src/blackmisc/interpolatorlinear.cpp
index 75b64029b..97d4d9b1d 100644
--- a/src/blackmisc/interpolatorlinear.cpp
+++ b/src/blackmisc/interpolatorlinear.cpp
@@ -60,8 +60,8 @@ namespace BlackMisc
         // interpolation situations
         CAircraftSituation oldSituation;
         CAircraftSituation newSituation;
-        status.interpolationSucceeded = true;
-        status.changedPosition = true; //! \todo efficiently determine whether the position has changed
+        status.setInterpolationSucceeded(true);
+        status.setChangedPosition(true); //! \todo efficiently determine whether the position has changed
 
         // latest first, now 00:20 split time
         // time     pos
diff --git a/src/blackmisc/simulation/aircraftmodellist.cpp b/src/blackmisc/simulation/aircraftmodellist.cpp
index 15ee92163..7fb4688fe 100644
--- a/src/blackmisc/simulation/aircraftmodellist.cpp
+++ b/src/blackmisc/simulation/aircraftmodellist.cpp
@@ -54,6 +54,16 @@ namespace BlackMisc
             return false;
         }
 
+        bool CAircraftModelList::containsCallsign(const CCallsign &callsign) const
+        {
+            return this->contains(&CAircraftModel::getCallsign, callsign);
+        }
+
+        bool CAircraftModelList::containsModelsWithAircraftAndAirlineDesignator(const QString &aircraftDesignator, const QString &airlineDesignator) const
+        {
+            return this->contains(&CAircraftModel::getAircraftIcaoCodeDesignator, aircraftDesignator, &CAircraftModel::getAirlineIcaoCodeDesignator, airlineDesignator);
+        }
+
         CAircraftModelList CAircraftModelList::findByModelString(const QString &modelString, Qt::CaseSensitivity sensitivity) const
         {
             return this->findBy([ & ](const CAircraftModel & model)
diff --git a/src/blackmisc/simulation/aircraftmodellist.h b/src/blackmisc/simulation/aircraftmodellist.h
index ed70f5052..ea3f49a58 100644
--- a/src/blackmisc/simulation/aircraftmodellist.h
+++ b/src/blackmisc/simulation/aircraftmodellist.h
@@ -65,6 +65,12 @@ namespace BlackMisc
             //! Contains model with model string or id
             bool containsModelStringOrDbKey(const BlackMisc::Simulation::CAircraftModel &model, Qt::CaseSensitivity sensitivity = Qt::CaseInsensitive) const;
 
+            //! Contains model for callsign
+            bool containsCallsign(const BlackMisc::Aviation::CCallsign &callsign) const;
+
+            //! Contains any model with aircraft and airline designator
+            bool containsModelsWithAircraftAndAirlineDesignator(const QString &aircraftDesignator, const QString &airlineDesignator) const;
+
             //! Find by model string
             //! \remark normally CAircraftModelList::findFirstByModelStringOrDefault would be used
             CAircraftModelList findByModelString(const QString &modelString, Qt::CaseSensitivity sensitivity = Qt::CaseInsensitive) const;
diff --git a/src/blackmisc/simulation/simulatedaircraftlist.cpp b/src/blackmisc/simulation/simulatedaircraftlist.cpp
index 83422b534..8c2e5c925 100644
--- a/src/blackmisc/simulation/simulatedaircraftlist.cpp
+++ b/src/blackmisc/simulation/simulatedaircraftlist.cpp
@@ -153,5 +153,18 @@ namespace BlackMisc
             return false;
         }
 
+        bool CSimulatedAircraftList::replaceOrAddByCallsign(const CSimulatedAircraft &aircraft)
+        {
+            const CCallsign cs(aircraft.getCallsign());
+            if (cs.isEmpty()) { return false; }
+
+            if (this->containsCallsign(cs))
+            {
+                int c = this->replaceIf(&CSimulatedAircraft::getCallsign, cs, aircraft);
+                return c > 0;
+            }
+            this->push_back(aircraft);
+            return true;
+        }
     } // namespace
 } // namespace
diff --git a/src/blackmisc/simulation/simulatedaircraftlist.h b/src/blackmisc/simulation/simulatedaircraftlist.h
index f5523ca65..fbd31c448 100644
--- a/src/blackmisc/simulation/simulatedaircraftlist.h
+++ b/src/blackmisc/simulation/simulatedaircraftlist.h
@@ -92,8 +92,9 @@ namespace BlackMisc
             //! Rendered?
             bool isRendered(const BlackMisc::Aviation::CCallsign &callsign) const;
 
+            //! Replace or add by callsign
+            bool replaceOrAddByCallsign(const CSimulatedAircraft &aircraft);
         };
-
     } //namespace
 } // namespace
 
diff --git a/src/plugins/simulator/fs9/fs9client.cpp b/src/plugins/simulator/fs9/fs9client.cpp
index 47c295db8..18aee1b7a 100644
--- a/src/plugins/simulator/fs9/fs9client.cpp
+++ b/src/plugins/simulator/fs9/fs9client.cpp
@@ -39,7 +39,7 @@ namespace BlackSimPlugin
             positionVelocity.lat_f = qAbs((latitude - positionVelocity.lat_i) * 65536);
 
             // Longitude - integer and decimal places
-            double longitude = newSituation.getPosition().longitude().value(CAngleUnit::deg()) * ( 65536.0 * 65536.0) / 360.0;
+            double longitude = newSituation.getPosition().longitude().value(CAngleUnit::deg()) * (65536.0 * 65536.0) / 360.0;
             positionVelocity.lon_hi = static_cast<qint32>(longitude);
             positionVelocity.lon_lo = qAbs((longitude - positionVelocity.lon_hi) * 65536);
 
@@ -96,7 +96,7 @@ namespace BlackSimPlugin
             positionSlewMode.lat_f = qAbs((latitude - positionSlewMode.lat_i) * 65536);
 
             // Longitude - integer and decimal places
-            double longitude = situation.getPosition().longitude().value(CAngleUnit::deg()) * ( 65536.0 * 65536.0) / 360.0;
+            double longitude = situation.getPosition().longitude().value(CAngleUnit::deg()) * (65536.0 * 65536.0) / 360.0;
             positionSlewMode.lon_hi = static_cast<qint32>(longitude);
             positionSlewMode.lon_lo = qAbs((longitude - positionSlewMode.lon_hi) * 65536);
 
@@ -119,7 +119,7 @@ namespace BlackSimPlugin
         }
 
         CFs9Client::CFs9Client(const CCallsign &callsign, const QString &modelName,
-            BlackMisc::IInterpolator *interpolator, const CTime &updateInterval, QObject *owner) :
+                               BlackMisc::IInterpolator *interpolator, const CTime &updateInterval, QObject *owner) :
             CDirectPlayPeer(owner, callsign),
             m_updateInterval(updateInterval), m_interpolator(interpolator), m_modelName(modelName)
         {
@@ -174,7 +174,7 @@ namespace BlackSimPlugin
             CAircraftSituation situation = this->m_interpolator->getInterpolatedSituation(m_callsign, -1, vtolAircraft, status);
 
             // Test only for successful interpolation. FS9 requires constant positions
-            if (!status.interpolationSucceeded) { return; }
+            if (!status.didInterpolationSucceed()) { return; }
 
             sendMultiplayerPosition(situation);
             sendMultiplayerParamaters();
diff --git a/src/plugins/simulator/fsx/simconnectobject.cpp b/src/plugins/simulator/fsx/simconnectobject.cpp
index cae8507e6..1452ac3b2 100644
--- a/src/plugins/simulator/fsx/simconnectobject.cpp
+++ b/src/plugins/simulator/fsx/simconnectobject.cpp
@@ -9,6 +9,9 @@
 
 #include "simconnectobject.h"
 
+using namespace BlackMisc::Aviation;
+using namespace BlackMisc::Simulation;
+
 namespace BlackSimPlugin
 {
     namespace Fsx
@@ -19,9 +22,83 @@ namespace BlackSimPlugin
             m_aircraft(aircraft), m_requestId(requestId)
         { }
 
+        bool CSimConnectObject::hasValidRequestId() const
+        {
+            return this->m_requestId >= 0;
+        }
+
+        bool CSimConnectObject::hasValidobjectId() const
+        {
+            return this->m_objectId >= 0;
+        }
+
+        bool CSimConnectObject::isPendingAdded() const
+        {
+            return !this->hasValidRequestAndObjectId() || !this->m_confirmedAdded;
+        }
+
+        bool CSimConnectObject::isConfirmedAdded() const
+        {
+            Q_ASSERT_X(!m_confirmedAdded || this->hasValidRequestAndObjectId(), Q_FUNC_INFO, "confirmed but invalid ids");
+            return m_confirmedAdded;
+        }
+
+        void CSimConnectObject::setConfirmedAdded(bool confirm)
+        {
+            m_confirmedAdded = confirm;
+            m_aircraft.setRendered(true);
+        }
+
+        void CSimConnectObject::setPendingRemoved(bool pending)
+        {
+            m_pendingRemoved = pending;
+            m_aircraft.setRendered(false);
+        }
+
         bool CSimConnectObject::hasValidRequestAndObjectId() const
         {
-            return this->m_requestId >= 0 && this->m_objectId >= 0;
+            return this->hasValidRequestId() && this->hasValidobjectId();
+        }
+
+        bool CSimConnectObjects::setSimConnectObjectId(int requestID, int objectId)
+        {
+            // First check, if this request id belongs to us
+            const int requestIntId = static_cast<int>(requestID);
+            auto it = std::find_if(this->begin(), this->end(), [requestIntId](const CSimConnectObject & obj) { return obj.getRequestId() == requestIntId; });
+            if (it == this->end()) { return false; }
+
+            // belongs to us
+            it->setObjectId(objectId);
+            return true;
+        }
+
+        CCallsign CSimConnectObjects::getCallsignForObjectId(int objectId) const
+        {
+            return getSimObjectForObjectId(objectId).getCallsign();
+        }
+
+        CSimConnectObject CSimConnectObjects::getSimObjectForObjectId(int objectId) const
+        {
+            for (const CSimConnectObject &simObject : this->values())
+            {
+                if (simObject.getObjectId() == objectId) { return simObject; }
+            }
+            return CSimConnectObject();
+        }
+
+        bool CSimConnectObjects::isKnownSimObjectId(int objectId) const
+        {
+            const CSimConnectObject simObject(getSimObjectForObjectId(objectId));
+            return simObject.hasValidRequestAndObjectId() && objectId == simObject.getObjectId();
+        }
+
+        bool CSimConnectObjects::containsPendingAdd() const
+        {
+            for (const CSimConnectObject &simObject : this->values())
+            {
+                if (simObject.isPendingAdded()) { return true; }
+            }
+            return false;
         }
     } // namespace
 } // namespace
diff --git a/src/plugins/simulator/fsx/simconnectobject.h b/src/plugins/simulator/fsx/simconnectobject.h
index 240800ff6..0a0358ed4 100644
--- a/src/plugins/simulator/fsx/simconnectobject.h
+++ b/src/plugins/simulator/fsx/simconnectobject.h
@@ -29,16 +29,16 @@ namespace BlackSimPlugin
             CSimConnectObject();
 
             //! Constructor
-            CSimConnectObject(const BlackMisc::Simulation::CSimulatedAircraft &aircraft,int requestId);
+            CSimConnectObject(const BlackMisc::Simulation::CSimulatedAircraft &aircraft, int requestId);
 
             //! Destructor
             ~CSimConnectObject() {}
 
             //! Get Callsign
-            BlackMisc::Aviation::CCallsign getCallsign() const { return m_aircraft.getCallsign(); }
+            const BlackMisc::Aviation::CCallsign &getCallsign() const { return m_aircraft.getCallsign(); }
 
             //! Simulated aircraft (as added)
-            BlackMisc::Simulation::CSimulatedAircraft getAircraft() const { return m_aircraft; }
+            const BlackMisc::Simulation::CSimulatedAircraft &getAircraft() const { return m_aircraft; }
 
             //! Set Simconnect request id
             void setRequestId(int id) { m_requestId = id; }
@@ -52,6 +52,27 @@ namespace BlackSimPlugin
             //! Set Simconnect object id
             int getObjectId() const { return m_objectId; }
 
+            //! Valid request id?
+            bool hasValidRequestId() const;
+
+            //! Valid object id?
+            bool hasValidobjectId() const;
+
+            //! Object is requested, not yet added
+            bool isPendingAdded() const;
+
+            //! Adding is confirmed
+            bool isConfirmedAdded() const;
+
+            //! Marked as confirmed
+            void setConfirmedAdded(bool confirm);
+
+            //! Removing is pending
+            bool isPendingRemoved() const { return m_pendingRemoved; }
+
+            //! Marked as confirmed
+            void setPendingRemoved(bool pending);
+
             //! VTOL?
             bool isVtol() const { return m_aircraft.isVtol(); }
 
@@ -62,7 +83,30 @@ namespace BlackSimPlugin
             BlackMisc::Simulation::CSimulatedAircraft m_aircraft;
             int m_requestId = -1;
             int m_objectId  = -1;
+            bool m_confirmedAdded = false;
+            bool m_pendingRemoved = false;
         };
+
+        //! Simulator objects (aka AI aircraft
+        class CSimConnectObjects : public QHash<BlackMisc::Aviation::CCallsign, CSimConnectObject>
+        {
+        public:
+            //! Set ID of a SimConnect object, so far we only have an request id in the object
+            bool setSimConnectObjectId(int requestID, int objectId);
+
+            //! Find which callsign belongs to the object id
+            BlackMisc::Aviation::CCallsign getCallsignForObjectId(int objectId) const;
+
+            //! Find which callsign belongs to the object id
+            CSimConnectObject getSimObjectForObjectId(int objectId) const;
+
+            //! Is the object id one of our AI objects?
+            bool isKnownSimObjectId(int objectId) const;
+
+            //! Pending add condition
+            bool containsPendingAdd() const;
+        };
+
     } // namespace
 } // namespace
 
diff --git a/src/xbus/traffic.cpp b/src/xbus/traffic.cpp
index a0f59142f..6168c61d3 100644
--- a/src/xbus/traffic.cpp
+++ b/src/xbus/traffic.cpp
@@ -308,8 +308,8 @@ namespace XBus
             {
                 BlackMisc::IInterpolator::InterpolationStatus status;
                 auto situation = m_interpolator->getInterpolatedSituation(plane->situations, -1, false, status);
-                if (! status.interpolationSucceeded) { return xpmpData_Unavailable; }
-                if (! status.changedPosition) { return xpmpData_Unchanged; }
+                if (! status.didInterpolationSucceed()) { return xpmpData_Unavailable; }
+                if (! status.hasChangedPosition()) { return xpmpData_Unchanged; }
 
                 using namespace BlackMisc::PhysicalQuantities;
                 using namespace BlackMisc::Aviation;
diff --git a/tests/blackcore/testinterpolator.cpp b/tests/blackcore/testinterpolator.cpp
index ed21c131b..504567e52 100644
--- a/tests/blackcore/testinterpolator.cpp
+++ b/tests/blackcore/testinterpolator.cpp
@@ -99,8 +99,8 @@ namespace BlackCoreTest
             CAircraftSituation currentSituation(interpolator.getInterpolatedSituation
                                                 (cs, currentTime, false, status)
                                                );
-            QVERIFY2(status.interpolationSucceeded, "Interpolation was not succesful");
-            QVERIFY2(status.changedPosition, "Interpolation did not changed");
+            QVERIFY2(status.didInterpolationSucceed(), "Interpolation was not succesful");
+            QVERIFY2(status.hasChangedPosition(), "Interpolation did not changed");
             double latDeg = currentSituation.getPosition().latitude().valueRounded(CAngleUnit::deg(), 5);
             double lngDeg = currentSituation.getPosition().longitude().valueRounded(CAngleUnit::deg(), 5);
             QVERIFY2(latDeg < latOld && lngDeg < lngOld, "Values shall decrease");
@@ -150,7 +150,7 @@ namespace BlackCoreTest
             IInterpolator::PartsStatus status;
             CAircraftPartsList pl(interpolator.getPartsBeforeTime(cs, ts, status));
             fetchedParts++;
-            QVERIFY2(status.supportsParts, "Parts not supported");
+            QVERIFY2(status.isSupportingParts(), "Parts not supported");
             QVERIFY2(!pl.isEmpty(), "Parts empty");
         }
         timeMs = timer.elapsed();