Another Boeing jet operated by United Airlines lost its main landing gear wheel while taking off on Monday, in a similar incident to a flight in March that helped trigger a federal safety review.
There were no reports of injuries among people on the ground or the 174 passengers and seven crew on United flight 1001, Bloomberg cited a airline spokesman as saying.
The Boeing 757-200 took off from Los Angeles at 7.16am local time and landed at Denver International Airport at 10.10am
The Federal Aviation Administration said it is investigating the incident.