Also, there is the reality of delays. Even trains can be delayed, although busses and planes are more likely to suffer from this.

Up, Up and... In-flight Internet service is starting to be provided by some airlines. But between time you spend in the security and boarding lines, and take-off and landing use prohibitions, the odds are that you can't use your notebook for more than half the travel time anyway.

Given a comparable-time choice, , says wireless industry analyst , founder of . "Air travel is now completely inefficient for business people: Few flights, always full, no power, no Internet access, and 'keep things off for take off and landing,'" he says. "The seats are now so close together [that] it's too uncomfortable to type, unless you've got an end seat or first class."

Take the A (for Acela) Train

Today's intercity rail can be a relaxing, productive experience. On , there's no security check, many (though not all) stations have good to-go food, and if you reserve your ticket online, you can get it from a kiosk machine. Trains like the , which runs from Boston through Washington, D.C., have seat tables and per-seat electric outlets.