Incase you get some time while you are at the airport of Kolkata due to a layover, you could actually do quite a bit of interesting things depending on your preferences. The nearest attraction that would be easy for you to reach is the market area where you will find many handicraft items and also street foods that you can taste here. One other nice place that you could go to while in Kolkata is Eco Park which is a very beautiful park in the city. The nearby Dakshineswar Kali temple is another great place which is not far from the airport. There are also various restaurants where you can try out authentic Bengali dishes.