It was already going down that road. 9/11 was just another excuse. Airline tickets used to be "bearer instruments" - there were no names on them, whoever presented the ticket was allowed to ride. The story is that airlines didn't like that because people would buy tickets (remember this was before hub and spoke, so mostly nonstop) and then resell them in the classified ads (no Craigslist then) in the newspaper for a profit. But I think that it was surveillance driven even then. Read about how many hijackings there were in the 60s and 70s. Yet no new measures were taken.