Heathrow Airport's Terminal 4 has reopened after a suspect bag sparked a security alert.
The departure lounge has been partially evacuated
The Metropolitan Police said an item was identified at the terminal at about midday on Tuesday but "nothing significant" was found after a search.
Thousands of departing passengers faced long delays as airport officials began re-screening them.
International flights were cancelled until the evening and European flights were cancelled for some time.
The alert came after failed terrorist attacks in London and Glasgow.
Following the alert the departure lounge at the terminal was partially evacuated and passengers were moved out on to the street and into the car park.
A Metropolitan Police spokeswoman said all air traffic from Terminal 4 was stopped while checks were carried out.
BAA said the suspect bag was identified shortly before 1200 BST.
BAA is advising concerned passengers to contact their individual airlines
British Airways: 08705511155
Kenya Airways: 02087597309
Iberia Airlines: 08706090500
TAM Brazilian Airways: 02088973700
A spokesperson said: "We have had to cancel 108 flights in total.
"Our flights to and from Terminal 1 at Heathrow are operating, but with some delays."
Terminal 4 is used by KLM, British Airways, Qantas, Kenya Airways, Iberia Airlines and Brazilian airline TAM.
Earlier on Tuesday a controlled explosion was carried out on a suspect device near Hammersmith Tube station.
During the morning rush-hour the station in west London and surrounding roads were closed when a suspect device was found at about 0825 BST.
There was an unconfirmed report the suspect objects had turned out to be three abandoned fire extinguishers.
Up to 8,000 commuters were forced to find alternative routes into work as Hammersmith and Barons Court stations were closed for an hour.
There were also severe delays for motorists as Hammersmith Broadway was closed between King Street and Shepherd's Bush Road as well as Hammersmith Bridge.
Tower Hill and East Ham Tube stations were shut during the morning rush-hour in a separate alert.