Background
I travel...a lot. I spend hundreds of hours a year in the air and countless more sitting in airports, cabs, hotels, and, of course, Starbucks. To complement this brutal travel schedule, I consistently have a crushing workload from the office. This combination has lead me to seek out, develop, and improvise a number of productivity strategies that seem to work well for a mobile lifestyle. When I analyze where I spend my time and how I spend my time, I have found that the number one productivity spot for me to get tangible work product accomplished is on the plane. When I refer to "tangible work product" I'm talking about the tasks that are creation oriented, not communication oriented; in other words things like creating presentations, reviewing material, crunching numbers, writing whitepapers, completing strategic planning exercises.
On an airplane, particularly when upgraded, I have everything I need. If you find you have problems getting into first class, take a look at First Class Upgrades for great hints and tips. I have seat power (at least on American Airlines, Continental and Southwest, the other two carriers that dominate my home market provide less power options), caffeine, and most importantly, no interruptions.
I have spent a lot of time ensuring that I get the most from my valuable plane time. I thought others could benefit from some of the tactics and processes I have put in place for myself.
When The Door Closes
My plane productivity begins when the airplane door closes. That signals the point at which the outside world can no longer reach out and demand my attention. Cell phones are turned off, laptops are stowed, and I have the choice of reading the airline magazine or getting productive.
I am paper free. Everything is digital and web accessible. The only exception I have allowed to this rule is a small Moleskin notebook 
that I use as the focal point of my plane productivity system. When the plane door closes, out comes my Moleskin, where I use the time until 10,000 feet (when electronic devices are one again permitted) to do some good old fashion strategic planning.
For each flight, I create a new page. On it I note some details on the flight, the top of mind projects I need to focus on, the next actions I will be working on while flying, and the things I need to take care of when I land. During the flight, I work this list and use it as a guide to ensure I get the most value out of my enforced solitude. After the fact, I process the information and add it to my trusted system (all electronic), so any value on the Moleskin pages no longer remain "locked" on paper.
At the top of the page, I note the details of the flight. 
This context is useful for three reasons. First, the date and time allows me, when processing the data later, to put it in historical context. I know how "stale" the information which allows me to better judge whether it is still relevant. Likewise, the city locations give me a hint as to what might have been on my mind at the time, which help me to understand why certain items were more important at the time. Lastly, the flight time, coupled with the time of takeoff allows me to keep track of how much time is left during the flight, which allows me to do better time management while the flight is underway.
Once I have the flight details written down (about ninety seconds), I note the "P1" projects down the left hand side. P1 is a slang term I use to denote the projects that are causing me the most stress either because of their urgency or their importance. By listing them, I get a sense of control over the stresses with which I am dealing. I may not do anything about them on the flight, but projecting them onto paper and objectifying them has a therapeutic effect. When I do tackle them on the plane, I often find that they can disappear as short term concerns entirely. Often, after focusing on a high stress project, I find that it no longer makes my P1 list on the next leg of the same trip. I general, I don't discriminate between personal and professional projects. In general my professional projects dominate the list, but the point is to reduce stress and take care of the fires with which I am dealing. That means that dealing with the logistics of a cross country move may be side by side with the problematic sales cycle that you were banking on to make your quarter.
After the P1 project list, I start on my "flight plan". The flight plan is the task list for the plane ride. I compose this list utilizing two methods. First, I quickly write down any urgent tasks that had my attention that day. This could include a critical email that I needed to write or voicemail response that needs some thought. I have found that brainstorming is a particularly effective plane activity, so I place weight on these tasks. Once my head is clear of stray tasks that have been floating around, but haven't made it to my master list, I focus on the P1 list. I go line by line and decide what next actions exist for that project. Often, I discover I have already covered one or more of these tasks in my first pass through the flight plan. to help my organize, I draw a line from the project to the task on the flight plan to visually show me how much attention each P1 project is getting.
Once I have my flight header, my P1 list, and my flight plan documented, if I am still not to ten thousand feet, I scan the flight plan for tasks that I can accomplish without my smartphone or laptop. 
In general, I am biased towards brainstorming tasks. I am fresher when I get on the plane than when I get off and fresh braincells produce better brainstorming results. My favorite brainstorm capture mechanism is a mindmap, though often a simple list of key phrases work as well. In the caption, you can see an example.
In the Air
Once airborne, I have two main categories of tasks.
First, I like to transfer any useful data out of my moleskin and into my trusted system. At the start of the plain ride, I usually focus on the "content" I may have generated in my moleskin. For example, if I did some brainstorming, I might transfer the hand drawn mindmap to MindManager or OneNote. Once that information has been transfered, I cross it out in the Moleskin so I know that information has been processes and the moleskin entry can be safely ignored.
Second, I work the flight plan. By this point, I have access to my laptop and smartphone, so I could fall back to my normal task management practices. However, I find that the focus and discipline of the flight plan and P1 approach means that following the flight plan provides higher value use of my time. As I work through the items on my flight plan, I cross them out on the page. If I clear my flight plan, I revert back to my standard task list.
On Descent
Once we start our approach into our destination, it is a race to "wrap up". There are a number of important tasks I accomplish in that short time.
I make sure that any important tasks from my flight plan are captured in my day to day task list. When I clear all the items off my page for that flight, including capturing any information like mind maps or lists I might have made, I put a large "X" on the top, outside corner of the page, so I know that I no longer need to revisit this information later.
As I am forced to turn off my laptop and phone again, I once again go back into my moleskin. This time I am focused on what I need to do when I land. I note phone calls I need to make, errands I may need to run in the airport, etc.
I also rate the effectiveness of the flight time. I see what I was able to get done and what I wasn't. I spend a moment reflecting on why I feel I was unable to complete tasks I thought I should. This minor process improvement strategy allows me to make surprising strides in productivity. While it is fresh on my mind, I am able to identify holes in my process and create strategies for dealing with them on future flights.
On the Ground
Once we land, I use the time while the plane taxis to the gate to make any calls that I had identified during descent. Once I work through those, I move on to my call list in my main task list. As we approach the gate, I pack up, relax and relish the feeling of accomplishment from another productive flight.
