Hopefully, summer will push 2014 movies in the right direction because things have been so bleak thus far that “Non-Stop” – a silly-but-enjoyable thriller – stands as a highlight. The movie, which allows Liam Neeson to continue his run as an action hero, is fun from start to finish, but it is equally convoluted, meaning anyone who values plausibility is left in the cold. Neeson plays Bill Marks, a troubled air marshal who – despite the requirements of his job – hates to fly.