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United Airlines passengers to see targeted ads on seat-back screens
(www.cbsnews.com)
This is a most excellent place for technology news and articles.
Until proven otherwise, I'd assume the worst. They know your identity to travel, and they link it with profiles from all the major ad networks.
I think you're spot on. In addition to needing to hand over your passport or state ID, your credit card, your email and phone number, what else would they need to target you?
Imagine if you're using your airline branded credit card to get free miles or a seat upgrade and they know all your purchase history.