English to French Art/Literary General / Conversation / Greetings / Letters Novel

Hi everybody,

I'm wondering what the term "the pin-stripe express" means. I couldn't find it anywhere, could it be slang? Maybe a private jet? The author is Scottish, if it helps any.
The context: one character in the novel got a lot of trouble in JFK airport with Immigration. Two other characters, very rich and with plenty of connections, have no problems entering the USA at all.

Here is the sentence:

"Flying into JFK on the pin-stripe express from London City Airport, they bypassed the Immigration queue entirely: they had their passports stamped by an obsequious immigration officer during the refueling stop at Shannon, along with a dozen bankers and discreetly ultra-rich fellow-travelers."

Thanks!