At 9:44, NORAD briefed the conference on the possible hijacking of Delta 1989.
( ( At 9:44 ) ( , ( NORAD ( ( ( briefed ( the conference ) ) ( on ( ( the ( possible hijacking ) ) ( of ( Delta 1989 ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN At) (NP (CD 9:44))) (, ,) (NP (NNP NORAD)) (VP (VBD briefed) (NP (DT the) (NN conference)) (PP (IN on) (NP (NP (DT the) (JJ possible) (NN hijacking)) (PP (IN of) (NP (NNP Delta) (CD 1989)))))) (. .)))
NORAD kept the possible hijacking of Delta 1989  to themselves.
( NORAD ( ( ( kept ( ( the ( possible hijacking ) ) ( of ( Delta 1989 ) ) ) ) ( to themselves ) ) . ) )
(ROOT (S (NP (NNP NORAD)) (VP (VBD kept) (NP (NP (DT the) (JJ possible) (NN hijacking)) (PP (IN of) (NP (NNP Delta) (CD 1989)))) (PP (TO to) (NP (PRP themselves)))) (. .)))