In C/C++ you first call SimConnect_AICreateSimulatedObject() to ask FSX to create the object, then it will call back with the SIMCONNECT_RECV_ID_ASSIGNED_OBJECT_ID message after it has been created (that also gives you the FSX object ID). Then call SimConnect_AIReleaseControl() to turn off AI control of that object, and call SimConnect_TransmitClientEvent() to that object with the messages FREEZE_LATITUDE_LONGITUDE_SET, FREEZE_ALTITUDE_SET and FREEZE_ATTITUDE_SET. That will turn off all physics processing.
Now you control the object and need to update its position and attitude with SimConnect_SetDataOnSimObject() either as often as you can (though you probably don't need more than 60 times per second), or subscribe to the FSX SIMCONNECT_RECV_ID_EVENT_FRAME event and send the updates in response to that.