The airlines bore responsibility, too.
( ( The airlines ) ( ( ( ( bore responsibility ) , ) too ) . ) )
(ROOT (S (NP (DT The) (NNS airlines)) (VP (VBD bore) (NP (NN responsibility)) (, ,) (ADVP (RB too))) (. .)))
The airlines were responsible because they'd let passengers on that looked suspicious.
( ( The airlines ) ( ( ( were responsible ) ( because ( they ( 'd ( ( let passengers ) ( on ( that ( looked suspicious ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NNS airlines)) (VP (VBD were) (ADJP (JJ responsible)) (SBAR (IN because) (S (NP (PRP they)) (VP (MD 'd) (VP (VB let) (NP (NNS passengers)) (PP (IN on) (SBAR (WHNP (WDT that)) (S (VP (VBD looked) (ADJP (JJ suspicious))))))))))) (. .)))