In the UI it would be nice to duplicate the selected connection, in the menu "With Selected". 

The copy would be set with the same name plus some suffix (_copy, _1, whatever) and it is useful for when you have a connection with all equal fields except something in a particular one. 
airflow/www/views.py
"""Duration calculation."""
        end_date = self.get('end_date')  
        duration = self.get('duration')  
        if end_date and duration:
            return timedelta(seconds=duration)
        return None
    formatters_columns = {
        'dag_id': wwwutils.dag_link,
        'task_id': wwwutils.task_instance_link,
        'start_date': wwwutils.datetime_f('start_date'),
        'end_date': wwwutils.datetime_f('end_date'),
        'execution_date': wwwutils.datetime_f('execution_date'),
        'reschedule_date': wwwutils.datetime_f('reschedule_date'),
        'duration': duration_f,
    }
class TaskInstanceModelView(AirflowModelView):
    """View to show records from TaskInstance table"""
    route_base = '/taskinstance'
    datamodel = AirflowModelView.CustomSQLAInterface(models.TaskInstance)  
    class_permission_name = permissions.RESOURCE_TASK_INSTANCE
    method_permission_name = {
        'list': 'read',
        'action_clear': 'edit',
        'action_set_running': 'edit',
        'action_set_failed': 'edit',