Airline companies in China reported more than 500 million yuan ($80.93 million) in net profits in March, up from a net loss of 130 million yuan in the same period last year.

However, most profits were due to investment and exchange gains, according to China Business News.

Airline carriers recorded more than 400 million yuan in exchange gains and more than 1 billion yuan in investment gains in March.

Figures from the Civil Aviation Administration of China show flight passengers in China increased 15 percent year-on-year to 28.78 million in March. Air cargo and mail carried increased 4 percent to 490,000 tons in March.