From The Telegraph:
By using a credit card to book a flight, passengers face having other transactions on the card inspected by the American authorities. Providing an email address to an airline could also lead to scrutiny of other messages sent or received on that account.
...
As a result the Americans are entitled to 34 separate pieces of Passenger Name Record (PNR) data — all of which must be provided by airlines from their computers.
Much of it is routine but some elements will prove more contentious, such as a passenger's email address, whether they have a previous history of not turning up for flights and any religious dietary requirements.
While insisting that "additional information" would only be sought from lawful channels, the US made clear that it would use PNR data as a trigger for further inquiries.
Anyone seeking such material would normally have to apply for a court order or subpoena, although this would depend on what information was wanted. Doubts were raised last night about the effectiveness of the safeguards.
