Drive in and out of Silguri. Bagdogra is the closest airport from Calcutta. It is about 20 km from Silguri. From Silguri the closest boarder town in Nepal is Kakarbhitta. It is about 30 km. You can either fly in from Calcutta to Bagdogra or take flight from Kathmandu to Biratnagar or Bhadrapur (in Nepal) and drive to Silguri