What holds these pieces of personal travel data together?

• Credit card number and expiration (really)
• IP address used to make web travel reservations
• Hotel information and itinerary
• Full Name, birth date and passport number
• Full airline itinerary, including flight numbers and seat numbers
• Cruise ship itinerary
• Phone numbers, incl. business, home & cell
• Every frequent flyer and hotel number associated with the subject, even ones not used for the specific reservation

If you said "a homeland security database", then you're right!