An ARJ21 jetliner of One Two Three Airlines (OTT Airlines) heads for designated area before performing its first flight at Shanghai Hongqiao International Airport in Shanghai, east China, Dec. 28, 2020. The ARJ21 is China's first turbo-fan regional passenger jetliner manufactured by the Commercial Aircraft Corporation of China (COMAC). OTT Airlines, a subsidiary of China Eastern Airlines, is the last among seven airlines to officially operate ARJ21 jetliner in China. (Xinhua/Ding Ting)

An ARJ21 jetliner of One Two Three Airlines (OTT Airlines) takes off at Shanghai Hongqiao International Airport to begin its first flight in Shanghai, east China, Dec. 28, 2020. The ARJ21 is China's first turbo-fan regional passenger jetliner manufactured by the Commercial Aircraft Corporation of China (COMAC). OTT Airlines, a subsidiary of China Eastern Airlines, is the last among seven airlines to officially operate ARJ21 jetliner in China. (Xinhua/Ding Ting)

Photo taken on Dec. 28, 2020 shows an ARJ21 jetliner of One Two Three Airlines (OTT Airlines) before performing its first flight in Shanghai, east China. The ARJ21 is China's first turbo-fan regional passenger jetliner manufactured by the Commercial Aircraft Corporation of China (COMAC). OTT Airlines, a subsidiary of China Eastern Airlines, is the last among seven airlines to officially operate ARJ21 jetliner in China. (Xinhua/Ding Ting)

An ARJ21 jetliner of One Two Three Airlines (OTT Airlines) heads for designated area before performing its first flight at Shanghai Hongqiao International Airport in Shanghai, east China, Dec. 28, 2020. The ARJ21 is China's first turbo-fan regional passenger jetliner manufactured by the Commercial Aircraft Corporation of China (COMAC). OTT Airlines, a subsidiary of China Eastern Airlines, is the last among seven airlines to officially operate ARJ21 jetliner in China. (Xinhua/Ding Ting)

Photo taken on Dec. 28, 2020 shows an ARJ21 jetliner of One Two Three Airlines (OTT Airlines) before performing its first flight in Shanghai, east China. The ARJ21 is China's first turbo-fan regional passenger jetliner manufactured by the Commercial Aircraft Corporation of China (COMAC). OTT Airlines, a subsidiary of China Eastern Airlines, is the last among seven airlines to officially operate ARJ21 jetliner in China. (Xinhua/Ding Ting)

An ARJ21 jetliner of One Two Three Airlines (OTT Airlines) heads for designated area before performing its first flight at Shanghai Hongqiao International Airport in Shanghai, east China, Dec. 28, 2020. The ARJ21 is China's first turbo-fan regional passenger jetliner manufactured by the Commercial Aircraft Corporation of China (COMAC). OTT Airlines, a subsidiary of China Eastern Airlines, is the last among seven airlines to officially operate ARJ21 jetliner in China. (Xinhua/Ding Ting)