Found a website saying Youtube adviews are $100-300 per 10k (ad views, not video views). That's 1-3¢ per view. If we assume an ad is 10seconds, then your time is worth 0.1-0.3¢ per second, or $3.60-10.80 per hour.
An A380 looks to be 380-615 seats. I'd imagine they're more often optimising for space, so let's say 550.
Long haul flight, 10% of people at any time using inflight stuff, 8 hours, 4 ads per hour = 5500.18*4 ads watched. 1760 ads. There will be a massive premium for planes, but surely only one order of magnitude more (e.g. 10x). That's equivalent to give or take 20k YouTube adviews which would be $200-600 per flight.
There are a lot of planes in the sky every single day though....
United Airlines passengers to see targeted ads on seat-back screens ( www.cbsnews.com )