The Vice President was mistaken in his belief that shootdown authorization had been passed to the pilots flying at NORAD's direction.
( ( The ( Vice President ) ) ( ( was ( ( mistaken ( in ( his belief ) ) ) ( that ( ( shootdown authorization ) ( had ( been ( passed ( to ( ( the pilots ) ( flying ( at ( ( NORAD 's ) direction ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NNP Vice) (NNP President)) (VP (VBD was) (VP (VBN mistaken) (PP (IN in) (NP (PRP$ his) (NN belief))) (SBAR (IN that) (S (NP (NN shootdown) (NN authorization)) (VP (VBD had) (VP (VBN been) (VP (VBN passed) (PP (TO to) (NP (NP (DT the) (NNS pilots)) (VP (VBG flying) (PP (IN at) (NP (NP (NNP NORAD) (POS 's)) (NN direction))))))))))))) (. .)))
The President authorized the pilots to shoot down hijacked planes.
( ( The President ) ( ( ( authorized ( the pilots ) ) ( to ( ( shoot down ) ( hijacked planes ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NNP President)) (VP (VBD authorized) (NP (DT the) (NNS pilots)) (S (VP (TO to) (VP (VB shoot) (PRT (RP down)) (NP (JJ hijacked) (NNS planes)))))) (. .)))