Pre 9/11, the government still knew what flight you were taking. You ID was checked at the gate just prior to boarding the plane, and the passenger manifests we

Pre 9/11, the government still knew what flight you were taking. You ID was checked at the gate just prior to boarding the plane, and the passenger manifests were uploaded to a federal database in real time. A similar process happens on trains and Greyhounds - your ID is checked and manifests are monitored - so those are not necessarily more incognito options. However, non-passengers (such as family members or friends) could accompany travelers to the gate, or meet them there when they disembark, passing through security without a ticket