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
"""Mark task as failed."""
        args = request.form
        dag_id = args.get('dag_id')
        task_id = args.get('task_id')
        origin = get_safe_url(args.get('origin'))
        execution_date = args.get('execution_date')
        upstream = to_boolean(args.get('failed_upstream'))
        downstream = to_boolean(args.get('failed_downstream'))
        future = to_boolean(args.get('failed_future'))
        past = to_boolean(args.get('failed_past'))
        return self._mark_task_instance_state(
            dag_id,
            task_id,
            origin,
            execution_date,
            upstream,
            downstream,
            future,
            past,
            State.FAILED,
        )
    @expose('/success', methods=['POST'])
    @auth.has_access(
        [
            (permissions.ACTION_CAN_READ, permissions.RESOURCE_DAG),
            (permissions.ACTION_CAN_EDIT, permissions.RESOURCE_TASK_INSTANCE),
        ]
    )
    @action_logging
    def success(self):