US Sikh organisations have expressed anger over changes allowing airport security staff to "pat down" turbans.
UK airports are considering introducing private turban searches
Until now turbans have been searched or removed only to resolve an unexplained alarm from an airport metal detector.
But now security will have greater discretion to inspect turbans so that they can be manually checked for objects such as non-metallic weapons.
However Sikh groups have responded to the new measures by describing them as outrageous and discriminatory.
Sikh men wear turbans to cover their hair, which they leave uncut in accordance with their religion.
Organisations representing Sikhs have only recently completed a publicity campaign to explain the significance of the kirpan, or religious sword, to security officials.
The Transportation Security Administration insisted the new policy was necessary to counter the threat of improvised bombs and chemical weapons.
In Britain, the government said recently that private searches of turbans might be necessary as part of airport security.