On a recent trip from Seattle to LAX, I noticed two notable avenues to the way passengers are exposed to advertising. The first was listening to a co-branded message between Alaska airlines and VISA credit cards, broadcasted by the pilot. It didn't seem to evoke much interest among the coach passengers. I'd say that it's more like we were too tired to care about another credit card offer. The second was a $20 coupon of a restaurant I'd never heard of which was handed out by a stewardess.
It's not surprising though. The Nov 2005 press release from UK-based Ink Publishing (ink-publishing.com) notes that "global inflight advertising revenues are predicted to grow from US $685 million in 2004 to US $832 million this year and will exceed US $1,010 million in 2006, with increased general advertising spending plus the opening of niche markets by point-to-point airlines taking credit for the growth." These sales figures are based on their own portfolio data of inflight titles they publish. You can imagine how tremendously large this market really is.
What is surprising is how late-to-market some airlines are with capturing their share of this revenue stream.