whether Gst is applicable on air freight on import of goods in India

YES, imports of Goods and Services will be treated as inter-state supplies and IGST will be levied on import of goods and services into the country. The incidence of tax will follow the destination principle and the tax revenue in case of SGST will accrue to the State where the imported goods and services are consumed. Full and complete set-off  
will be available on the GST paid on import on goods and services.