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
abort,
    before_render_template,
    current_app,
    escape,
    flash,
    g,
    jsonify,
    make_response,
    redirect,
    render_template,
    request,
    session as flask_session,
    url_for,
)
from flask_appbuilder import BaseView, ModelView, expose
from flask_appbuilder.actions import action
from flask_appbuilder.fieldwidgets import Select2Widget
from flask_appbuilder.models.sqla.filters import BaseFilter  
from flask_appbuilder.security.views import (
    PermissionModelView,
    PermissionViewModelView,
    ResetMyPasswordView,
    ResetPasswordView,
    RoleModelView,
    UserDBModelView,
    UserInfoEditView,
    UserLDAPModelView,
    UserOAuthModelView,
    UserOIDModelView,
    UserRemoteUserModelView,