The White House said the US airport security agency is desperately working to balance travellers' privacy concerns with security needs. Spokesman Robert Gibbs said the controversial new screening would evolve with travellers' input. This week is one of the busiest for U.S airports with millions set to travel for Thursday's Thanksgiving holiday.At the White House on Monday, Mr Gibbs said President Barack Obama's highest priority was to ensure that when you or I or others get on to an airplane that we can feel reasonably sure that we can travel safely.