If I'm in an airline, I should have some say if there's going to be a camera facing me the ... entire ... flight. That goes beyond just the casual picture or video capture.
In the USA, it depends on jurisdiction and the circumstances. For example, CA is a "two-party consent" state, meaning that to record another party requires their knowledge and consent in some circumstances. This case (a camera in the back of an airline seat) is a bit on the line: the space isn't terribly private (it's a row of seats on an airline), yet a private conversation might be had in a low voice between two people, who did not see, or do not recognize, and were not told that there is a camera pointed right at them.
I do not know if this is a violation of two-party consent. It might not be.
IANAL, but AFAIK one/two party consent only applies to private conversations (eg. phone calls). Public conversations are fair game in all jurisdictions.
If their commercial purpose was internal to the company then a release wouldn't be required.
I'm an American. This likely isn't true in other countries with more stringent privacy laws.