Crisis managers at the FAA and the airlines did not yet act to warn other aircraft.
( ( ( Crisis managers ) ( at ( ( ( the FAA ) and ) ( the airlines ) ) ) ) ( ( ( ( did not ) yet ) ( act ( to ( warn ( other aircraft ) ) ) ) ) . ) )
(ROOT (S (NP (NP (JJ Crisis) (NNS managers)) (PP (IN at) (NP (NP (DT the) (NNP FAA)) (CC and) (NP (DT the) (NNS airlines))))) (VP (VBD did) (RB not) (ADVP (RB yet)) (VP (VB act) (S (VP (TO to) (VP (VB warn) (NP (JJ other) (NN aircraft))))))) (. .)))
Crisis Managers had already began warning other aircraft.
( ( Crisis Managers ) ( ( had ( already ( began ( warning ( other aircraft ) ) ) ) ) . ) )
(ROOT (S (NP (JJ Crisis) (NNS Managers)) (VP (VBD had) (VP (ADVP (RB already)) (VBD began) (S (VP (VBG warning) (NP (JJ other) (NN aircraft)))))) (. .)))