John Levine wrote:
A packed business jet will be less comfortable than a commercial flight.

if that is the case I don't see the selling point

If they fly to Westchester and the actual goal is, say, IBM
headquarters, that's a 10 minute drive from Westchester, but a 60 to
90 minute slog from JFK.

If they go to LaGuardia, it's less pronounced but still significant.
To, say, the Citibank tower in Manhattan, it's 30 mins from LGA, an
hour from JFK.

Somewhere like Westchester sounds like a more sensible base for an exec jet
service than an existing large commercial airport, though LGA would
certainly beat JFK.