The equipment isn't now, nor has ever been, the problem.
The problem is the cost to the end-user. Just what are you intending to charge me for it? Because if it's expensive, I'll wait until I get off the plane. And most people run scared of roaming anyway - there's a reason for that that's nothing to do with worrying about using foreign airwaves or interfering with the plane, or the slight delay in voice traffic. It's simply the cost.
So every time you equip a plane, you're expecting people to fund its installation by using it and making you a proportion of profit after you've connected via a satellite and talked to a (now foreign) mobile operator to terminate your calls. And then you price it so extortionately that the only reason people REALLY turn their phones off on a plane is because they're scared they'll hit roaming charges while they're not looking.
Seriously, people. Sod all the fancy stuff. Let me send texts and browse the web. You can cache that locally, send it at your own leisure, don't care about slight interruptions, can route via the cheapest method transparently (wireless / 3G while on the ground, switch to satellite once high enough in the air) and not bother me with people shouting "HELLO!" down the phone while I'm trying to sleep. Then you can price it more sensibly and shock, horror, people might start to use it. While things are still priced in pounds per megabyte, nobody is going to EVER touch the service except by accident or curiosity.
Nothing else, absolutely nothing else, matters but the cost to the end-user. If you charge me 5p extra to send a text message that you then relay over some hugely-slow but viable link back to a base in the UK that then sends the text message onwards from there, that would be useful. If you let me have available-but-slow wifi, that's worth a couple of quid per flight, maybe, if I need it. Anything else and no matter how much a captive audience you have, nobody will touch it. Real-time voice just isn't necessary - we're only amusing ourselves until the plane lands when we THEN do all the important phone calls anyway. Give us the most basic of data services at a *decent* price and you'd have an audience.
Mobile networks need to realise that mass volume of customers * a couple of pence profit is infinitely better than no customers * huge wads of profit each. This applies to roaming, data, data roaming, and airplane use. Drop your prices, see a rise in profits. Increase the prices to these stupid amounts, see a continued absence of customers afraid to even turn their phones ON abroad and instead buying a foreign SIM, thus netting you 0p profit.