A month after President Biden invoked the Defense Production Act to import emergency supplies of infant formula, store shelves are still half empty and brands shipped on U.S. military planes from other countries are not yet helping many families struggling to find critical specialty brands. The U.S. government began importing infant formula from Switzerland, the United Kingdom and elsewhere one month ago. It launched Operation Fly Formula to address a shortage that was triggered by the COVID-19 pandemic, a major formula recall and a decision by the FDA to shutter one of the nation’s top formula-producing plants for several months...