In my opinion, the most important statement in the latter acts of the play is the letter that Larry sent to Ann just before he commits suicide.  In the letter, Larry says that the war is a place where no man is responsible only for himself.  He feels the bonds between himself and the other soldiers around him who are dying for someone else's cause.  He also says that the men in charge of giving orders play the soldiers like pawns and do not respect the fact that lives are on the line.  So Larry suggests that he is going to down his own plane as both an act of comradery and a statement of protest.

Larry's letter reveals several key themes in the play, so the only statement that comes from him in the play is important.