30 years ago it was possible to check into a good US hotel with cash under an assumed name. That is pretty much impossible now; they want to see your ID and a credit card.
It might still be possible to pay cash in fleabag hotels; I don't know.
A few more than 30 years ago it was possible to buy plane tickets from the classified pages from people who, for whatever reason, couldn't take the flight.
And of course the ticket was in their name, but no one cared. It was treated by the airlines like a purchased token. You had the token, you flew.
Try 60 years ago. I'm not sure when the change happened but 30 years ago cards were required. In 60+ year old books it is common for the 'dective' to look in the hotel book and find a false name.
It might still be possible to pay cash in fleabag hotels; I don't know.