On January 17, 2018, with the flight HU7781 departing from Haikou Meilan Airport, Hainan Airlines became the first airline in China to provide in-flight WiFi Services. On the next day, China Eastern Airlines also launched flights with WiFi services available. Passengers taking planes marked with WiFi symbols are allowed to use portable electronic devices (PED), such as mobile phones, pads, laptops, electronic readings, and game machines.

The two airlines are not alone. Spring Airlines, a budget airline in China, expressed explicitly that they were promising to allow PED use in the first half of 2018. Southern Airlines and Air China are also planning to follow the step.
  In recent years, whether mobile phones can be used on plane is always a hot topic, with people's increasing dependence on mobile phones. The Civil Aviation Administration of China has loosened the in-flight use of mobile phones since October 2017 and authorized airlines to make decisions at their own discretion. From then on, airlines in China have been engaged in researches on in-flight WiFi service feasibility.

Compared with China, most airlines in European and American countries began to allow passengers to use mobile phones long before.
  Mobile phones, laptops, electronic books, audio / video players, game machines, etc.

Notice that mobile phones should be switched to flight mode and Cellular Mobile Communication Function should be turned off. Mobile phones without flight mode are forbidden. It means passengers are still not able to make a call on the plane or access internet by cellular data.

PEDs exceeding regulated specifications cannot be used when the plane is taxing, taking off, descending and landing.
  Currently, China Eastern Airlines and Hainan Airlines offer free in-light WiFi access for passengers. It's predicted that some airlines may charge passengers, either by data traffic or online duration.
  In the "high speed train vs. flight" battle, WiFi services may help flights to gain a point. Many passengers choose to take high speed trains because it's boring on a plane as their mobile phones must be turned off. Now that WiFi is accessible in the air, they may turn back to flights. In addition, onboard WiFi services make in-flight payment possible. In the near future, passengers may pay on the plane for services, duty-free goods, or class upgrade by mobile phones.