Earlier quoted context omitted.
He is not entirely wrong about the capacity limits of the railway stations, though. European cities struggle with inadequate railway capacity all the time. The main problem is that the original railway stations were laid out in about 1840-1870, for much smaller passenger streams, and today find it hard to cope with modern requirements (a lot of commuters from the suburbia). But given that there is dense city infrastr…
If you have no space for larger train station, then you will have problem to fit airport there. Or even commuting infrastructure to reach airport.
People can tolerate a longer commute to the airport and back, because few Europeans commute by air daily. Most of us fly at most several times a year.