European airlines do not charge bag fees. The flights leave on time, and I have never once seen an argument over overhead space. Completely full flights board in 10 minutes. Plus my violin always gets on the plane happily.^
US Airlines charge ridiculous prices for checking bags. Flights generally leave a little bit late, and nearly every US domestic flight I've been on has had 20 bags gate-checked. Completely full flights generally board in 30-40 minutes.
I can't figure out why there is such a big difference!