They assumed the fighter escort would be discreet, vectored to a position five miles directly behind the hijacked aircraft, where it could perform its mission to monitor the aircraft's flight path.
( They ( ( assumed ( ( the ( fighter escort ) ) ( would ( be ( ( ( ( discreet , ) ( vectored ( to ( ( a position ) ( ( five miles ) ( directly ( behind ( the ( hijacked aircraft ) ) ) ) ) ) ) ) ) , ) ( where ( it ( could ( perform ( its ( mission ( to ( monitor ( ( the ( aircraft 's ) ) ( flight path ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP They)) (VP (VBD assumed) (SBAR (S (NP (DT the) (NN fighter) (NN escort)) (VP (MD would) (VP (VB be) (NP (NP (NN discreet)) (, ,) (VP (VBN vectored) (PP (TO to) (NP (NP (DT a) (NN position)) (ADVP (NP (CD five) (NNS miles)) (RB directly) (PP (IN behind) (NP (DT the) (JJ hijacked) (NN aircraft))))))) (, ,) (SBAR (WHADVP (WRB where)) (S (NP (PRP it)) (VP (MD could) (VP (VB perform) (NP (PRP$ its) (NN mission) (S (VP (TO to) (VP (VB monitor) (NP (NP (DT the) (NN aircraft) (POS 's)) (NN flight) (NN path)))))))))))))))) (. .)))
The fighter jets stayed far enough away to track the plane.
( ( The ( fighter jets ) ) ( ( ( stayed ( far ( enough away ) ) ) ( to ( track ( the plane ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN fighter) (NNS jets)) (VP (VBD stayed) (ADVP (RB far) (RB enough) (RB away)) (S (VP (TO to) (VP (VB track) (NP (DT the) (NN plane)))))) (. .)))