Definitely - and it’s nowhere near the carbon emissions so I think what happened is that they saw someone else’s data (hopefully inadvertently) comparing a mostly full long haul flight (148gm CO2/passenger/kilometer) to a city bus (97g) rather than the long-distance buses you mentioned which are far more efficient since they don’t stop frequently (27g).
They used to. When I was growing up, way before budget airlines, buses used to be the way you traveled around Europe for cheap.