I think in practice there are reasonable and bloody awful airports in both Europe and the US.
One thing I do find to be better, in general, in European airports is that they have thought more about how people will actually get to and from the airport; generally, you get there, you follow a sign, and you get on a bus, train, or get to a taxi rank. US airports (my sample's relatively small, but at least SFO and SEA) seem to enjoy making this awkward. For instance, when you get off the train to SEA, you seem to have to walk about a kilometre _through a parking garage_; bizarre arrangement. If you want to get an Uber/Lyft from there, you go to a random poorly signposted place in said parking garage.
Actually, now I think of it, last time I was in SF I got a bus to the airport, and that _also ended up in a random parking garage_.
One thing I do find to be better, in general, in European airports is that they have thought more about how people will actually get to and from the airport; generally, you get there, you follow a sign, and you get on a bus, train, or get to a taxi rank. US airports (my sample's relatively small, but at least SFO and SEA) seem to enjoy making this awkward. For instance, when you get off the train to SEA, you seem to have to walk about a kilometre _through a parking garage_; bizarre arrangement. If you want to get an Uber/Lyft from there, you go to a random poorly signposted place in said parking garage.
Actually, now I think of it, last time I was in SF I got a bus to the airport, and that _also ended up in a random parking garage_.