The flight attendants would have begun their cabin service.
( ( The ( flight attendants ) ) ( ( would ( have ( begun ( their ( cabin service ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN flight) (NNS attendants)) (VP (MD would) (VP (VB have) (VP (VBN begun) (NP (PRP$ their) (NN cabin) (NN service))))) (. .)))
The flight attendants would have begun their cabin service by now if the plane wasn't hijacked.
( ( The ( flight attendants ) ) ( ( would ( have ( ( ( begun ( their ( cabin service ) ) ) ( by now ) ) ( if ( ( the plane ) ( ( was n't ) hijacked ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN flight) (NNS attendants)) (VP (MD would) (VP (VB have) (VP (VBN begun) (NP (PRP$ their) (NN cabin) (NN service)) (PP (IN by) (NP (RB now))) (SBAR (IN if) (S (NP (DT the) (NN plane)) (VP (VBD was) (RB n't) (VP (VBN hijacked)))))))) (. .)))