From what I've read about the Boeing idea, it's a lot like DirectPC satellite Internet access (the two way kind) accessible through an onboard LAN. What Boeing did was develop an electronically scanned conforming satellite antenna that helps the DirectPC connection work as the platform is moving at 500 kts.
Click here to access the Boeing site
The Tenzing Communications idea simply periodically downloads pages from selected sites and uploads them with a low bandwith reciever to to give you the illusion that you're accesing the internet.
I like the Boeing idea, because I could use my own computer and it's capable of very high speeds, as well as giving me the whole Internet.
The Tenzing system is for use in seat back TVs; even if it was accesible through some sort of LAN, I would have to deal with crummy slow access speeds. Not my cup of tea.