Sweatpants on a Plane: First Impression vs. Ongoing Dialogue

There are people, though I am definitely not among them, that get dressed up when traveling, just in case of that chance, in transit encounter that might change your life. The underlying principle behind this no-sweatpants while flying philosophy is that everyday is a first impression. And you should always make the most of a first impression.

I still prefer sweats for flying. But I'm wondering if all this concern over first impressions is just silly--you can blow all your effort by simply opening your mouth if you have nothing of substance to say.

So here's another one of those, what's more important questions: first impressions or ongoing dialogue?

Issues of false dichotomy aside, I'd prefer to be judged by the content of my character (and head) than my appearance. Appearance based first impressions lack understanding of personal depth and intellect--usually that requires some semblance of an ongoing relationship.

But what do you think?