Can I use Huabei to buy air tickets on the same trip?

No. Tongcheng is a travel app on WeChat and does not authorize Alipay as a payment method. Huabei is a payment method of Alipay. They are two independent softwares produced by two independent companies. Huabei cannot be used. Tongcheng Travel is a company jointly established by Tongcheng Network and elong Travel Network under Tongcheng Travel Group on December 29, 2017. The new company will integrate the transportation, hotel and other advantageous resources of both parties to create a more leading travel service platform.