One of Sydney Airport's runways was shut for 35 minutes after a pilot reported seeing debris while coming in to land about 7.40am on Friday.
Sydney Airport spokeswoman Tracy Ong confirmed that Sydney's third runway, running north-south, was closed between 7.45 and 8.20am so the report could be investigated, resulting in the diversion of three flights.
Sydney's main runway, a 4.5-kilometre stretch of tarmac also running north-south, was not affected and continued to operate at capacity.
The 35-minute closure resulted in the diversion of one Qantas Airways and two United Airlines flights.
The United Airlines flights were diverted to Canberra because both were coming from Los Angeles and were nearing their fuel limits.
Ms Ong confirmed all flights would be back in Sydney by the afternoon.
The Herald received reports from a passenger on board one of the United Airlines flights, saying they had been parked on the tarmac at Canberra International Airport for more than three hours, were not allowed out of their seats and had to wait for a new crew because their crew was "over time".
If only CBR was a true international airport rather than just taking the name in vain.