we are willing to travel from kathmandu to shanghai and Beijing by air. How much is the air ticket?

From Katmandu to Shanghai or Bejing, you have to transfer the flight in Guangzhou Baiyun International Airport. And the exact ticket fare cannot be estimated because the price will change with seasons.

In ordinary time, from Katmandu to Shanghai, the whole single trip costs around CNY 3,500.
From Katmandu to BJ, the ticket fare is CNY 3,200 to 3,500.