Direct Duke to strengthen its policies and procedures related to purchasing airfare that will be charged to a Federal project. Updated procedures could include: a. Requiring travelers to document the business purpose of each day of a planned trip before purchasing airfare to enable Duke to evaluate whether it must perform a travel comparison to support that airfare costs did not increase as a result of personal travel. b. Requiring travelers to maintain documentation to support compliance with the Fly America Act and, if a deviation is required, maintain documentation that supports the costs relate to an allowable Fly America Act exception. c. Requiring travelers to justify and document any conditions that resulted in an allowable need to purchase upgraded airfare, as required by Federal regulations. d. Updating its foreign travel policies to provide specific guidance regarding the allowability of business-class airfare on federally sponsored awards, including how the traveler should document the cost of comparable economy-class airfare.