China Eastern Airlines says it has missed a golden opportunity to improve its financial and management performance.

On Aug. 11, CEA shares fell 7.94 percent to a 19-month low of HK$1.97 after the deadline on an agreement to sell a stake to Singapore Airlines expired.

"I am not sure whether the shareholders feel the same pain, if they felt as disappointed as we do. We could have brought CEA's debt-to-equity ratio down from 95 percent to 80 percent, if the SIA and Temasek capital injection plan had been realized," CEA director Luo Zhuping said.

"There may be misunderstandings in the market because there are different ways to bring in investors. But the SIA and Temasek deal could have been a real asset, both in terms of capital and management expertise," Luo added.

CEA's H shares jumped 75 percent to HK$6.53 when the deal was first announced on Sep. 4 last year.

Luo said when CEA unlocked its H shares after it signed the agreement with SIA and Temasek, they rocketed from HK$2.50 to HK$6.80.