Following an agreement between the European Commission and U.S. Authorities - signed on 14 May 2004 (complete document [here]), European airlines are now required to hand-over 34 data items from Passenger Name Records (PNR) to U.S. Authorities.

Airlines who refuse to hand over the data will be fined up to USD 6000 per passenger carried to the U.S.
Passenger who refuse to have their data shared with U.S. authorities can be barred from travelling to the United States.

Under the agreement, no less than 34 data items are transferred to the US
authorities. These data will be stored for 3,5 years (or 8 years, for auditing purposes, for data files that have actually been accessed)
as opposed to the 50 years time limit, originally requested by the US.

Under the current agreement:

• US authorities have promised to filter out such sensitive data as meal orders or other special requirements that might reveal race, religion or personal health info.
• PNR data is only used to combat and prevent terrorism, terrorism-related crimes and serious crimes, including organised crime of a trans-national nature, instead of a much wider range of law enforcement uses previously sought by the US.
• US authorities will only share PNR data on a case-by-case basis, and only for the agreed purposes. There will be no bulk-sharing of PNR data. Further, US authorities cannot distribute the data to other countries without notification of a designated EU authority.
• Most PNR data will be deleted after 3,5 years (compared with up to fifty years originally emanded by the US). Files that have been accessed will be kept in a deleted data file for a further eight years for auditing purposes (compare with 'indefinitely', as originally intended).
• The agreement is valid for three years, and needs to be expressly
  extended at the end of that period of time.

• PNR record locator code
• Date of reservation
• Date(s) of intended travel
• Name
• Other names on the PNR
• Address
• All forms of payment information (including credit card details)
• Billing address
• Contact telephone numbers
• All travel itinerary for the specific PNR
• Frequent flyer information (limited to addresses and miles flown)
• Travel Agency
• Travel Agent
• Code Share PNR information
• Travel status of passenger
• Split/Divided PNR information
• Email address
• Ticketing field information
• General remarks
• Ticket number
• Seat number
• Date of ticket issuance
• No show history
• Bag tag numbers
• Go show information
• OSI (Other Service Information)
• SSI/SSR information (Special Service Information/Request)
• Received from information
• All historical changes to the PNR
• Number of travellers on the PNR
• Seat information
• One-way tickets
• Any collected APIS-information
• ATFQ Fields