Protesters have targeted the base
Two men are being questioned by police after being arrested at RAF Fairford on suspicion of aggravated trespass.
A 17-year-old from Wales and 22-year-old from Leamington Spa were being held at Stroud police station after allegedly breaking through the perimeter fence at about 2300 GMT on Wednesday.
A 45-year-old woman from Hampshire was arrested earlier in the day outside the base for unlawful obstruction of the highway.
She was released after admitting the offence and being cautioned at Cirencester police station.
Wednesday's arrests are the latest in a series at the airbase where 14 American B-52 bombers have been based since early March.
Gloucestershire Police say 58 people have been arrested at the base since the end of January.