Federal regulators want to ban the sale of most flavored e-cigarettes at retail locations like gas stations and convenience stores. They also want to require anyone buying e-cigarettes online to verify their age. The new restrictions come as the Food and Drug Administration has been trying to rein in a dramatic increase in vaping by young people. Smoking of traditional tobacco cigarettes has fallen to a record low, but the popularity of e-cigarettes among youth is raising alarm bells.