Special stop and search powers under anti-terrorism laws are in force in Wiltshire and Gloucestershire.
Gloucestershire Police have stepped up security around Fairford
A police spokeswoman said the powers had been introduced to enhance security around RAF Fairford.
A Gloucestershire police spokeswoman said the enhanced powers came into force at 1920 GMT on 7 March and would last until 2 April.
"The order covers the counties of Gloucestershire and Wiltshire and gives police the power to stop and search persons and vehicles in order to prevent terrorism."
We're very concerned that the authorities operate in a legal and
But peace campaigners at the Gloucestershire base, where American B-52 bomber planes are stationed, said they were concerned legitimate protest might be affected.
Dave Cockcroft said: "We've got legal people looking at this at the moment but we're very concerned that the authorities operate in a legal and legitimate way.
"We're non-violent protesters and believe we have a right to protest and what we're seeing at the moment is the wholesale destruction of democracy."