The travel requisition functionality in Dynamics 365 is used to approve the travel before it occurs.  This is worthwhile functionality.  An additional feature of the travel requisition is it could be used to book travel once it is approved as well when travel bookings are handled centrally.  To facilitate this process the travel requisition form could be expanded to include fields such as flight required details out and return including departure date and time, origin, airline preference, accommodation preference and location of stay.