CHENNAI: Airports Authority of India has sought nearly 1000 acres from the Tamil Nadu government for expansion activities at airports in Chennai Coimbatore and Tiruchirappalli, a senior official said today.AAI Chairman Guruprasad Mohapatra said the state government has also been asked to identify 2-3 locations for establishing a second airport near Chennai to cater to its growing demands."All big cities will require two airports... we will require a minimum of 2000 acres for a greenfield airport," he told reporters here.He said 200 acres of land has been sought from the state government for expansion of the existing airport here.Further, a request has been placed for allocation of 300 and 450 acres of land for the expansion of the airports at Coimbatore and Tiruchirappalli, respectively, he said.Plans were on to demolish and re-construct an existing structure at Chennai airport at an estimated Rs 2500 crore, works for which are likely to start later this year and expected to be completed in three years, Mohapatra said.This, in addition to the proposed expansion activties, will enable increasing flight operations here from 32 per hour to 40 while passenger footfall will go up from 18 million to 30 million annually by 2020, he said.Tamil Nadu Chief Minister K Palaniswami has been 'briefed' on the land requirement for these purposes and he was "positive" on looking into the matter, he said.On Tamil Nadu coming on board the Regional Connectivity Scheme (RCS), he said it would augur well for the state, adding, the first flight was expected to fly into Salem and Neyveli by September this year.The state government had earlier in the day inked a pact with the Civil Aviation Ministry for implementing the Centre's UDAN (Ude Desh ka Aam Naagrik) scheme, connecting Salem and Neyveli, besides Hosur.