Could Air Tickets be Free?

Could an airline subsidise air ticket to almost zero cost, through in-air advertising?

In-air advertising could be on the audio-video system provided in (some) planes, or poster on the walls and roofs, or pamphlets in the back-pockets.

You think people would simply close their eyes in deep meditation to skip the advertisements? Then lets do this - they get a refund on their ticket based on a quiz they take before they deplane - the quiz tests them on the ads they saw during the flight!

But realistically, how much would advertisers pay for an in-flight ad. Or put another way, how much would one pay for a person's attention? Let go about it in a systemic manner - lets begin with how much advertisers pay for TV spots or newspaper ads. Then we can move onto calculating the attention span of a customer. More of these in later posts.