Richard Anderson, CEO of Delta, said: "Delta's investment in China Eastern shares is an investment into the promising future of the partnership. China is the second-largest travel market for the US and it will be the largest one in few years."

Delta and China Eastern already operate 30 domestic routes in the US, 43 domestic routes in China and seven cross-Pacific routes through a code-sharing arrangement, at present.

The strategic cooperation between the two carriers will allow them to further connect to each other's network.

The two airlines together hold about 26 percent of the capacity share in the Sino-US air traffic market, just behind United Airlines' with a 29 percent stake, said a report published by Sinolink Securities.

On the other hand, the cooperation can also help Delta strengthen its position in Shanghai, which may replace the carrier's other hubs in Asia in the future. Anderson told Bloomberg in April that the carrier plans to build a hub in Shanghai.

Delta has already moved to Terminal 1 at the Shanghai Pudong International Airport, where China Eastern is located, and it will be more convenient for passengers to transfer between the two carriers.