Hello. According to the Beijing Municipal Bureau of Culture and Tourism, the free layover tour services at the airport are provided by Ctrip International Travel Service. Please check the following link for more details: https://www.trip.com/hot/beijingexpress-halfdaylayovertour/. 

For specific information, please contact Ctrip International via E-mail: BeijingExpress@trip.com. 

Thank you for your understanding and support!