Which document requires a Sign Up Stamp as proof of registration?

The requirement for a Sign Up Stamp as proof of registration specifically pertains to Space-A (Space Available) travel orders. This stamp signifies that a traveler has officially registered and has been acknowledged for their intent to utilize Space-A travel.

Space-A travel allows eligible military personnel and their dependents to fly on available flights, which necessitates an official record of their intent to travel. The Sign Up Stamp serves as a verification process that ensures the orders are properly logged and that the passengers have met any prerequisites for using this travel option.

In contrast, the other documents listed do not specifically require a Sign Up Stamp. For instance, a Passenger Ticket typically verifies that a ticket has been purchased, while a Travel Itinerary outlines the schedule and details of travel but does not serve as an official registration for Space-A travel. Similarly, a Flight Manifest is a list of passengers on a specific flight but does not incorporate the registration process attached to Space-A travel. Therefore, the significance and need for the Sign Up Stamp is unique to Space-R travel orders, aligning them explicitly with the requirements for registration in this context.