China Postal Airlines has signed a contract with PEMCO World Air Services for five Boeing 737-300 converted freighters, National Business Daily reported on Thursday.

The airlines, which operates express mail and cargo transport services mainly for China Post, is expected to operate a cargo fleet of at least 26 planes next year, after buying five B737 cargo freighters from Shandong Air in April, according to China Postal Airlines.

In its long-term strategy, China Postal Airline is planning on having 46 aircraft in five years and 90 airplanes by 2023 while other private Chinese couriers build up their fleets.

SF Express, one of the largest couriers in China, said that its fleet of aircraft will reach 30 in the near future, including chartered planes. YT Express plans to have 15 aircraft in three years and launch its air cargo company in 2014.