The Air Force Thunderbirds canceled a performance a day after two of the group's F-16s made contact in flight, causing an object from one plane to plummet into Lake Michigan.
The aerial acrobatic team cut short its performance Saturday when two of the jets touched while flying in a diamond formation. A 4-foot-long missile rail came loose from one of the wings and fell into the water 2,500 feet from spectators on Chicago's lakefront.
The team said it would not perform again until an investigation could be completed.
The last time two Thunderbird jets were reported to have made contact in the air was in 1999.