Amazon Inc is planning to expand its futuristic cashier-less Go stores at airports. The stores are expected to ease frequent time-crunched flyers. Amazon has started entering mortar and building form of retail targeting shoppers' spending. Shoppers can make purchases at Go stores using just a smartphone. Go stores equipped with camera and sensors can identify the item and deduct the bill from credit card using an app. Seven such stores from online giant has started in Chicago, San Francisco and Seattle in the US.