A fighter plane of U.S. air force Thunderbirds performs during the 60th Annual Chicago Air and Water Show over North Avenue Beach in Chicago, the United States, Aug. 18, 2018. The two-day Chicago Air and Water Show began on Saturday. (Xinhua/Wang Ping)

U.S. Coast Guard perform during the 60th Annual Chicago Air and Water Show over North Avenue Beach in Chicago, the United States, Aug. 18, 2018. The two-day Chicago Air and Water Show began on Saturday. (Xinhua/Wang Ping)

An aerobatics aircraft performs during the 60th Annual Chicago Air and Water Show over North Avenue Beach in Chicago, the United States, Aug. 18, 2018. The two-day Chicago Air and Water Show began on Saturday. (Xinhua/Wang Ping)

U.S. air force Thunderbirds perform during the 60th Annual Chicago Air and Water Show over North Avenue Beach in Chicago, the United States, Aug. 18, 2018. The two-day Chicago Air and Water Show began on Saturday. (Xinhua/Wang Ping)

U.S. air force Thunderbirds perform during the 60th Annual Chicago Air and Water Show over North Avenue Beach in Chicago, the United States, Aug. 18, 2018. The two-day Chicago Air and Water Show began on Saturday. (Xinhua/Wang Ping)