( ( Generally ( ( moving ( from east ) ) ( to west ) ) ) ( , ( ( the ( jet stream ) ) ( ( is ( responsible ( for ( ( shortening ( flight times ) ) ( for ( ( European ( bound flights ) ) ( from ( the ( United States ) ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (S (ADVP (RB Generally)) (VP (VBG moving) (PP (IN from) (ADVP (JJ east))) (PP (TO to) (NP (NN west))))) (, ,) (NP (DT the) (NN jet) (NN stream)) (VP (VBZ is) (ADJP (JJ responsible) (PP (IN for) (S (VP (VBG shortening) (NP (NN flight) (NNS times)) (PP (IN for) (NP (NP (JJ European) (JJ bound) (NNS flights)) (PP (IN from) (NP (DT the) (NNP United) (NNPS States)))))))))) (. .)))
Generally moving from east to west, the jet stream is responsible for shortening flight times for European bound flights from the United States.
(ROOT (S (NP (NP (DT The) (JJS best) (NN explanation)) (PP (IN for) (SBAR (WHADVP (WRB how)) (S (NP (NN air) (NNS masses)) (VP (VBP move) (PP (IN across) (NP (DT the) (VBN united) (NNS states)))))))) (VP (VBZ is) (SBAR (IN that) (S (NP (DT the) (VBG prevailing) (NNS westerlies)) (VP (VP (VBP move) (NP (NN air) (NNS masses)) (PP (IN from) (NP (NN west))) (PP (TO to) (ADJP (JJ east))) (PP (IN across) (NP (DT the) (VBN united) (NNS states)))) (CC but) (VP (MD may) (VP (VB be) (VP (VBN deflected) (PP (IN by) (NP (DT the) (NN jet) (NN stream)))))))))) (. .)))