The Lisbon police force said that the operation, which began last Thursday, netted several airport workers and two others who did not work in the airport.
The police said the suspects “repeatedly and discretely stole objects that were easily accessible in the luggage in the planes’ holds and that could be hidden before being removed from the restricted areas of the airport.
The police said the favoured items to be stolen were electronic equipment, jewellery, watches, glasses and cash.