Adding to this, I suspect that in Europe customers are more effectively sorted between full service and low cost carriers, with almost all business travel on full service carriers and the vast majority of leisure travelers now using LCCs/ULCCs. By contrast, in the USA, business travelers sometimes choose WN or even Frontier, Spirit, etc. if the routes and schedules are better that what legacy carriers offer. In Europe, everyone is much more likely to use trains than in the USA, especially away from the northest corridor (and possibly the California coast). In the USA, the leading alternative to flying would be driving.

In terms of (full service) airline policies themselves, lounge access rules are very different in the USA versus EU as are most fare rules, with discounted exEU tickets generally being totally unchangeable versus most exUSA tickets being changeable for a fee even though cancellation usually results in a voucher rather than a refund. EC261 versus USA DOT regulations are very different too, starting with the definition of IDB.