Yes. However, the traveler should not purchase airline tickets for trips that include
personal travel which is a higher price than the airline ticket for the business-only trip. A documented airfare comparison is helpful to show no additional costs were incurred.
For example, you attend a conference that ends on Wednesday night. Instead of flying back the next morning, you decide to stay in town until Saturday on personal travel. When you book the flight to return on Saturday, you notice that it is more expensive than the Thursday morning return flight. Travel policies state that you will need to reimburse the university for the difference.