Unlike in the early 70s when something like "Airport" with its mild language, mild violence and talk about illegitimate pregnancies still got a G rating, today I think the mild language and general nasty tone would alone give it a PG, apart from the scary scenes, reckless driving, and don't forget the smoking and drinking. It's actually hard to get a G today.
That's because it's become ridiculously more limited in scope. Even a puff on a cigarette will do it. For instance, "The Artist" was to me clearly a G (it got the equivalent tag in some other countries), The affable tone of the movie was such that the mild bits of mayhem or whatever were hardly an issue to fret over. Even PG movies are deemed a tad too lightweight nowadays, so scads of dramas with little prompting get the ideal marketing ploy of PG13. Hey, at least we have RIO 2 with a G, definitely going against the trend!