Concerns over the safety of other aircraft began to mount.
( ( Concerns ( over ( ( the safety ) ( of ( other aircraft ) ) ) ) ) ( ( began ( to mount ) ) . ) )
(ROOT (S (NP (NP (NNS Concerns)) (PP (IN over) (NP (NP (DT the) (NN safety)) (PP (IN of) (NP (JJ other) (NN aircraft)))))) (VP (VBD began) (S (VP (TO to) (VP (VB mount))))) (. .)))
The safety of the other aircraft was ensured, there were no concerns.
( ( ( ( The safety ) ( of ( the ( other aircraft ) ) ) ) ( was ensured ) ) ( , ( there ( ( were ( no concerns ) ) . ) ) ) )
(ROOT (S (S (NP (NP (DT The) (NN safety)) (PP (IN of) (NP (DT the) (JJ other) (NN aircraft)))) (VP (VBD was) (VP (VBN ensured)))) (, ,) (NP (EX there)) (VP (VBD were) (NP (DT no) (NNS concerns))) (. .)))