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
payload.append(
                {
                    'dag_id': dag_id,
                    'active_dag_run': active_dag_runs,
                    'max_active_runs': max_active_runs,
                }
            )
        return wwwutils.json_response(payload)
    def _mark_dagrun_state_as_failed(self, dag_id, execution_date, confirmed, origin):
        if not execution_date:
            flash('Invalid execution date', 'error')
            return redirect(origin)
        execution_date = timezone.parse(execution_date)
        dag = current_app.dag_bag.get_dag(dag_id)
        if not dag:
            flash(f'Cannot find DAG: {dag_id}', 'error')
            return redirect(origin)
        new_dag_state = set_dag_run_state_to_failed(dag, execution_date, commit=confirmed)
        if confirmed:
            flash(f'Marked failed on {len(new_dag_state)} task instances')
            return redirect(origin)
        else:
            details = '\n'.join(str(t) for t in new_dag_state)
            response = self.render_template(
                'airflow/confirm.html',
                message="Here's the list of task instances you are about to mark as failed",
                details=details,
            )
            return response
    def _mark_dagrun_state_as_success(self, dag_id, execution_date, confirmed, origin):