The final six American B-52 bombers have arrived at RAF Fairford in Gloucestershire.
Eight B-52s arrived at the base on Monday
Fourteen of the giant bombers are to be stationed at the base, from where they will be expected to take part in any air assaults on Iraq.
Eight planes flew in on Monday, and the first of a further six landed at 1115 GMT on Tuesday.
Earlier police arrested a peace protester at the base.
Anni Rainbow, of the Campaign for the Accountability of American Bases, said 61-year-old Lindis Percy from Hull had wandered around the site.
Ms Rainbow said: "She just climbed over the fence, she didn't cut into it as she never damages them.
'Suspicion of aggravated trespass'
"She spent around four hours walking around inside the base - two hours spent underneath one of the planes.
"Not a single security patrol came up in that time."
The Ministry of Defence (MoD) confirmed the perimeter fence was breached but refused to comment on the claim that Ms Percy had been able to reach the jets.
An MoD spokesman said: "An inquiry will be held into this matter."
A police spokesman said: "We can confirm a 61-year-old woman from Yorkshire was arrested on suspicion of aggravated trespass.
"She is currently at Cheltenham police station, where she is due to be questioned later today."
It is thought the woman had been trying to take down a United States flag when detained.
Police have stepped up patrols at the Gloucester RAF and USAF base, where they have also invoked special stop-and-search powers.
Defence Minister Geoff Hoon granted permission for the B-52 bombers to be stationed at Fairford.
It is one of only three forward USAF bases outside America and is now capable of housing the B-2 bomber since undergoing a £100m refurbishment in 2002.