Shares of Air China and China Eastern Airlines both plummeted more than 9 per cent for the second day in a row in Shanghai yesterday as investor hopes of profiting from a wave of consolidation in the mainland aviation sector dimmed. A proposed counterbid by Air China's parent and Cathay Pacific Airways to trump a HK$7.2 billion tentative tie-up between Singapore Airlines and China Eastern was aborted on Monday after being blocked by the State Council. A shares of Air China, which is 80.6 per cent controlled by state-owned China National Aviation Holding (CNAH), fell 9.99 per cent to close at 22.43 yuan after shedding 10 per cent on Tuesday. China Eastern lost 9.72 per cent to 17.83 yuan after slipping 9.98 per cent on Tuesday. China Eastern's A shares had surged 138 per cent by Friday last week on speculation of a bidding war after the September 2 announcement that Singapore Airlines and Temasek Holdings would pay HK$3.80 per share for H shares representing a 24 per cent stake in the Shanghai-based carrier. Air China's A shares rose 44 per cent during the period, compared with a 2.29 per cent gain in the Shanghai Composite Index. The downturn followed Monday night's announcement by Cathay and CNAH that they were aborting the planned counterbid for the China Eastern stake. The companies declined to explain the decision.