Thinking out of the box, and for Someone i know who would like to see something of Europe but who doesnt want to fly, a cruise which originates in NY or Boston, goes to Europe, does two or three ports there and returns to US.
And perhaps there are some Brits who would like to see some of the US but also don’t want to fly so maybe a cruise originating Southampton, coming to the US to Boston, New York, and maybe one or two others and then return to Southampton.