Uh, that's because he's the POTUS! His position demands that he travel more than, practically, anyone in the world. (I wonder who travels more frequently than the POTUS...) If he stays in Crawford or the WH for more than a couple of days, they bitch about that he's not doing enough. Ridiculous.
And if he DIDN'T travel, the deekhead who wrote this article would be complaining that he was too isolated and should get out more. I think if we divide the president's fuel costs among the nearly 300 million of us he represents, we can probably handle the tab.