See Travel Policy – Section XVI Q: What is an Electronic Ticket (e-ticket) and how is it reported on a Business Expense Reimbursement Form?
An Electronic Ticket is Air travel reserved with an airline for which no paper ticket is issued. The reservation and seat assignment are secured within the airline’s computer reservation system only. The traveler must request a receipt from the travel agent or airline at the time of the booking or check-in at the airport in order to properly report the trip.