Explainer - London's new runway: progress at last but no take off yet

British lawmakers could approve the expansion of Heathrow this month, moving London's largest airport closer to building a new runway than it has been for years, but hurdles remain after decades of indecision and false starts.Owned by Spain's Ferrovial, Qatar Investment Authority and China Investment Corporation among others, Heathrow is Europe's busiest airport but is now operating at full capacity.Heathrow says the runway would be operational by 2026.