The president has long complained that the United States pays more for medicines than other wealthy countries. But he offered no clear legal authority to mandate lower prices.

IAG, the airline’s parent company, announced the order a day after Britain and the United States confirmed the framework for a trade agreement to lower tariffs.

President Trump on Wednesday signed an executive order targeting college accreditors, a group of largely unknown but long-established companies that evaluate the educational quality and financial health of universities. The order, one of seven …