"Apps users like to make quick decisions but PC users often make reservations ahead of time. About 40 percent of those who are using our apps do so in the middle of their overseas tours," Zhang says.

Shen Zhenyu, executive vice-president of popular travel search engine Qunar.com, says the growing mobile Internet market will surpass the PC Internet market, in both flow and profit, in the future.

In 2014, the company's revenue from mobile Internet was 708.7 million yuan ($114.3 million), an increase of 434.9 percent over 2013.

Some foreign apps are also competing in the market by localization and cooperation with others.

"As we move around the planet, apps are providing locations and context. There are many interesting things to do on apps. For example, the best time to recommend a restaurant is when you arrive at the airport," says Gareth Williams, cofounder and CEO of global travel search site Skyscanner. Chinese users are in the top four.