The fact that metropolitan areas in the northeastern United States are often divided among more than one state tends to complicate regional planning in an unfortunate way.He's right, but I think the problem exists outside of the northeastern United States. Throughout history humans have been better at moving resources over water then over land. As a result we have tended to settle and build cities on rivers and in bays. In the US we also used rivers to help divide up the States. This left us with a number of cities that have suburbs in 2 or 3 different states. Many are in the Northeast (New York, DC, Philadelphia). But they also exist in the midwest (Cincinnati, St. Louis, Kansas City).
I don't know enough about countries in Europe but I imagine that the problem exists there as well, but they might not have the same complex federalism problems. Canada is really big and there are only a few major cities so its not really an issue. Heres a cool map showing the US divided by population: