Interested firms can submit RFQ documents for the modernisation, operations and management of the four airports - Chennai, Kolkata, Japiur and Ahmedabad-- by August 31, 2015, according to the AAI website.
The earlier deadline for submission of documents was August 1.
The state-run airport operator, however, did not specify the reason for the further in the deadline.
The original deadline of March 24 was first extended to May 26 and then to July 1. However, the state-run operator failed to meet this deadline also and further extended the time period to August 1.
Private corporate including Tata and Adani groups and existing airport operators GMR and GVK groups besides some foreign players have shown interest in the these airports following the RFQ.