Are you willing to pay $8 or so for wifi access on the plane? Boom, you have mosh access.

I mean, yes, I get what you're saying, but I think it's at least plausible that the long-term solution for "doing developer things on the iPad" is going to involve network access and The Cloud™ for heavy lifting. (Granted, I think long-term, the distinction between local and remote everything is going to progressively blur over the coming years.)

[Edited to note: I think "Xcode for iOS" or an equivalent is almost certainly on the road map. I'm not sure whether full-blown web development of the "I am running a local web server on my iPad to test things" variety" is, although thinking about it, I can imagine ways a "LAMP App for iOS" might be implementable even today.]