The Rev Dan Woodhouse, a Methodist minister in Leeds and Sam Walton, a Quaker, are accused of entering the BAE Systems site in Warton to disarm planes.
Police said they were being held on suspicion of criminal damage.
In a statement, Rev Woodhouse said stopping warplanes "would save lives".
Rev Woodhouse added: "Stopping or even delaying Saudi Arabia having more planes with which to bomb Yemen would save innocent lives and prevent war crimes."
BAE Systems said the matter was being investigated by Lancashire Police and it was assisting officers with their inquiries.
Two people have been arrested in Lancashire after allegedly trying to disarm warplanes bound for Saudi Arabia.