Racist or Not?

I received the above photo in an e-mail recently with a caption that read....

An investigation by the NTSB in conjunction with the FBI has determined the cause of what brought down the plane in the Hudson River .

I'm curious about people's reaction to this joke. It's amazing the connotations a simple article of clothing can carry. So, I ask you. Is it racist or not? Or is it making fun of people who think anyone who wears a turban is a terrorist?

Discuss.