Tata Realty and Infrastructure is preparing a possible joint venture with Heathrow Airport's biggest shareholder, Ferrovial SA of Spain, to bid for the Navi Mumbai airport project. Ferrovial SA is one of the worlIf approved, the venture will mark the entry of the Spanish player into India's airport sector. It will also bring the Tatas one step closer to fulfilling their aims to be big in the India's aviation industry.