At that point in time, the Langley pilots did not know the threat they were facing, did not know where United 93 was located, and did not have shootdown authorization.
( ( At ( ( that point ) ( in time ) ) ) ( , ( ( the ( Langley pilots ) ) ( ( ( ( ( ( ( ( did not ) ( know ( ( the threat ) ( they ( were facing ) ) ) ) ) , ) ( ( did not ) ( know ( where ( ( United 93 ) ( was located ) ) ) ) ) ) , ) and ) ( ( did not ) ( have ( shootdown authorization ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN At) (NP (NP (DT that) (NN point)) (PP (IN in) (NP (NN time))))) (, ,) (NP (DT the) (NNP Langley) (NNS pilots)) (VP (VP (VBD did) (RB not) (VP (VB know) (NP (NP (DT the) (NN threat)) (SBAR (S (NP (PRP they)) (VP (VBD were) (VP (VBG facing)))))))) (, ,) (VP (VBD did) (RB not) (VP (VB know) (SBAR (WHADVP (WRB where)) (S (NP (NNP United) (CD 93)) (VP (VBD was) (VP (VBN located))))))) (, ,) (CC and) (VP (VBD did) (RB not) (VP (VB have) (NP (NN shootdown) (NN authorization))))) (. .)))
The Langley pilots were fully aware of the threat and situation and had authorization.
( ( The ( Langley pilots ) ) ( ( ( ( ( were ( fully aware ) ) ( of ( the ( ( threat and ) situation ) ) ) ) and ) ( had authorization ) ) . ) )
(ROOT (S (NP (DT The) (NNP Langley) (NNS pilots)) (VP (VP (VBD were) (ADJP (RB fully) (JJ aware)) (PP (IN of) (NP (DT the) (NN threat) (CC and) (NN situation)))) (CC and) (VP (VBD had) (NP (NN authorization)))) (. .)))