Doctor David Dao suffered serious injuries after refusing to give up his seat.
In line with rules governing the Inspector General's Office, the report didn't reveal the disciplined officers' identities.
The Department of Aviation ultimately fired the officer who "improperly escalated the incident" and the sergeant who tampered with the incident write-up, according to the report.
The dragging, captured on video by another passenger and spread on social media, involved Dr. David Dao, who declined to leave an overbooked United flight. The report added that the fired officers "grieved their discharge and arbitration dates have yet to be scheduled".
In light of the damning report, the Department of Aviation made a decision to terminate a security officer who allegedly "improperly escalated" the April 9 incident and the sergeant accused of redacting facts from an employee report, according to the local paper. The investigation also found that employees had made misleading statements and "deliberately removed material facts from their reports".
Video of the incident, which shows the 69-year-old being dragged off the flight by security officers as passengers looked on horrified, went viral and made worldwide headlines.
He urged Evans to "fully consider the serious issues identified" in his quarterly report during that review to make certain aviation security officers and their bosses "have a clear and consistent understanding of their roles and responsibilities-individually and in relation to CPD and other airport personnel".
Despite Dao's plea, the airline insisted and as a result, they sent security onto the plane, where they were told to remove him from the aircraft.
But viral video of the incident fast became an worldwide symbol of passenger discontent with the flying experience and a civic embarrassment that damaged Chicago's reputation as an global tourist destination.
"United has taken full responsibility for what happened on Flight 3411, without attempting to blame others, including the city of Chicago", Dao's attorney, Thomas Demetrio, said in a statement.