I have some good experience travelling with wine.
Regarding air pressure, my anecdote is, that there is little affect in an aircraft. However, this won't worry many here, but oxidisation rates seem to be considerable for an open bottle.
I don't buy wine at auction much. I prefer to buy wine ASAP after release, and place it in a professional storage facility. My wines consistantly drink best withing 5km of a cellaring facility.
Travel shock may or may not effect many wines. In my experience, it has a profounda effect on old wines in an unfiltered style.
I have consumed the same bottles of wines in this style, within 5km of my celllaring facility, with a consistant quality. The style will throw a considerable crust- sometimes for presentation at dinner parties, I will double decant and remove the crust simply by filling the empty, crusted bottle with springwater.
Now, when I take these wines back to Hong Kong say, and open within a few months, there is no crust! The travel has cleaned the crust and deposited it as floaties in the wine. Affecting wine quality considerably- gritty and tart!