MCO 4650.39A governs Marine Corps Defense Travel System administration, travel procedures, help desks, accounting, debt, fraud, and outage processes.
View MCO 4650.39A on armypubs.army.mil
It sets requirements for travel authorizations, reservations, cancellations, expenses, receipts, reports, naming conventions, and cross-organization funding. It also establishes processes for travel debt, waivers, fraudulent claims, internal controls, training, and emergency DTS outages.
Travelers who have an individual Government Travel Charge Card (GTCC) are required to use it for mandatory expenses per references (h) and (i). (paragraph 2)
Travel authorizations, which include air travel, not approved and ticketed at least 72 hours in advance of the scheduled flight departure are automatically canceled. (paragraph 3)
The traveler shall select the lowest cost rental car in DTS. (paragraph 3)
All receipts for airfare, rental car, and lodging shall be uploaded as a substantiating record into DTS (no matter the cost). (paragraph 1-5)
Requests shall be made 60 days prior to the requested start date. (paragraph 3)