The first US cabinet member to appear before the European parliament asked members to share data in the fight against terrorism.
Homeland Security Secretary Michael Chertoff told the EU's civil rights committee that access to information on transatlantic air passengers was crucial to help prevent future terrorist attacks.
'None of us wants to forsake our civil liberties in the name of security, on the contrary,' Secretary Chertoff said.
He later told reporters that the US needs to keep the data for longer than the current guidelines.
The agreement that says data can be stored for up to eight years expires at the end of July and both sides are trying to negotiate a new arrangement.
Post-11 September, European airlines agreed to pass on up to 34 items of passenger data including addresses and credit card details, in order to land at US airports.
EU lawmakers have criticised US methods for fighting terrorism, particularly secret CIA rendition flights that have landed at a number of European airports.
A recent EU report found that planes used for those flights landed at Irish airports more than 100 times.
Some members of parliament asked for more proof that the air data deal was useful, but criticism was muted.
