For me this is an easy one. Travelling overland wins for me. However, sometimes it is necessary to fly for many reasons, such as time, water (big problem here, unless you can find a nice boat) etc. Mostly though, I will opt for travelling by any means possible on the land. Not only is it cheaper, but you get to see so much more and interact with locals (who may often find you a comical site – particularly on a hard seat in the middle of China). It points to an all round more interesting journey. Add into that my fear of flying and you have a clear cut winner.
During our time in Asia last year, we took so many different methods of transport that didn’t involve flying; bus, train, catamaran, motorbike, bicycle, tuktuk, songthaew, mini bus, junk boat, long tail boat, kayak (I must admit this wasn’t used as a journey from A to B complete with backpacks, but should be in the list none the less), cable car (same can be said for this) and cyclo. That’s off the top of my head, there could well be more. Most of the time on our journeys, we would get a chance to interact with local people, which often proved to be most entertaining for all parties involved, as well as seeing some jaw-dropping beauty from the comfort (sometimes) of our seat. None of this can be done from thousands of miles in the sky and if you have the time and means to travel slowly and on the road, do it. A million times over.