Many of the old aircraft have been given to public parks and schools. These aircraft are completely stripped of all all equipment, armament, instruments, engines. So in fact they are only aircraft fuselages. As a rule they are distributed to public bodies and institutions,
not to individuals. The cost of transportation and maintenance is borne by the organisation receiving the aircraft. The IAF through the nearest ED or BRD assists to set up the display.
Of course Defence establishments have preference, for instance the NDA and AFA have large collections scattered about their campuses.
Old aircraft like the Spitfire and Hurricane are very few in number and a real rarity. BTW, nobody but nobody is allowed to restore and old military aircraft to flyable condition except the Armed Forces.
Check out the site- Warbirds of India. A lot of information is available along with history and pictures of old aircraft there.
Warbirds of India