Air travel used to be a classy affair. Think of the characters on Mad Men. They're all dressed to the nines for air travel. Over time, however, Americans became lazier, and so did their outfits for planes, trains, and automobiles.
People realized that they were simply getting dressed up to sit in one place, and that would not stand. Their finery was just garnering wrinkles, not attention. These days, you'd be hard-pressed to find an airport that wasn't 80 percent people in pajamas.
I must confess that I am one of them. My typical airport wear consists of yoga pants, a T-shirt, and Chucks. Even then, I silently curse myself for the Converse. They're a huge bother in the security line when you're flailing to grab your bag of liquids from the belt, jam it back in your suitcase, while simultaneously shoving your feet back into your shoes so you're not cleaning the airport floor. Then, of course, you have to find someplace to sit down and tie them.
I'm guessing Lady Gaga's airport experience is extremely different from my own, which is why she still treats flying like the fine fashion show it was back in the day. Fans eagerly await her arrival when she gets off the plane, and the Lady does not disappoint. She's currently touring airports in Asia (she's doing other things over there as well), and every outfit she wears to fly is a gift to the fashion gods.