Sinagpore\'s Changi Airport are going to have the capacity to handle 135 million passenger movements a year by the mid-2020s, when the airport\'s fifth terminal starts operation, Josephine Teo, Minister of State for Transport who is chairing the Changi 2036 steering committee, said on Friday. Changi Airport currently have three terminals operating, with a total passenger handling capacity of 66 million passengers per year. It recorded a total passenger movements of 51.2 million in 2012. The fourth terminal, which is under construction and upgrading work and formerly know as the budget terminal, will raise the total capacity of the airport to 85 million passenger per year by around 2020. The fifth terminal is initially designed to have the capacity to handle 50 million passenger movements a year -- larger than twice of the capacity of Terminal 1. It will be one of the largest terminals in the world. Teo said two conceptual options for the layout of Terminal 5 have been developed with various considerations such as passenger convenience and airfield and terminal operations efficiency in mind. The concept plan is expected to be finalized in the first half of 2014. The airport will also begin operating on a three-runway system from around 2020, instead of the current two. The existing runway 3, currently used by the military, will be extended from 2.75 km to 4 km to handle larger passenger aircraft. The city-state\'s Ministry of Transport said planning and preparatory works for the project have already started.