Spanish construction group Ferrovial, owner of London's Heathrow airport, said Tuesday its net profits plunged 43 percent in 2012 after major one-off gains the previous year. "The 42.9 percent decline in net profit is attributable to the extraordinary gains obtained in 2011," which totalled just over one billion euros, it said in a statement. "A significant portion of that figure did not represent a cash inflow since it was attributable to the revaluation of Heathrow Airport Holdings," Ferrovial said.