er, taste. Taste. That is all.

Just don't let them get a test for meat and we should be OK.

Well, if it is methanol, that's not too hard to find at a
hardware store, but the airlines may not want you bringing a
gallon on board. Then there is the issue of the waste/exhaust.
A hydrogen fuel cell just has pure water coming out, but other
fuels will have more waste. Johnny Walker from the beverage
cart will probably leave a big mess.

This is starting to sound like laptops with digestive tracks.

Or a two hour fuel cell, but I can just squirt more fuel cell stuff into it from my handy-dandy fuel cell container and get two more hours?

I wonder what the limiting factor is? Because honestly I can carry around a pretty big bottle of whatever fuel it requires if I need to. I was talking about this with a coworker once. I already have to carry around a laptop case, etc. What if the bottom 1 inch of the carrying case was just a fuel container and I plug a hose from there into the laptop?

Alternately, what if the carrying case has the fuel cell itself in it? it could be made larger and with a larger capacity and I could just plug a DC cord straight from there into my laptop.

Can we have a 20-hour fuel cell in a year instead?

Dude, Ethanol fuel cells are right behind.
The Liquor Laptop is right around the corner. No more messing with tangly power cables when a slug of Johnny Walker poured into your powerbook does the deed.

This sounds great; I just hope that at the end of that 40 hours, there'll be some hydrogen or liquid methanol lying around to recharge it...