I don't think anyone has properly answered your question which is about wearing traditional muslim clothes at the airport.
I can't either but I can tell you a little story a working colleague told me once.
A friend of his (German with Turkish descent) travelled from Berlin to New York. In the US, he was denied entry because he previously also travelled to South-East Turkey (which is where his family is coming from). They thought he was an IS fighter who went to this part of Turkey so he could easily cross the Syrian border.
His German passport didn't help him either. He had to fly back immediately.
So if you've been to any place close to Syria (and probably Iran, Afghanistan etc. as well), you will likely be denied entry too.