No idea. I would assume the US wasn't the only people trying to stay warm.
We were in Burbank with the Collings B-24 and B-17 in 2001. I had purchased a "new in the box" pair of the heated trousers and my wife was taking them home with her via the airline. The pants were packed in her carry-on and as she went through screening a stern screener asked her to "step in this room please". She sorta freaked out thinking that I must of crashed the B-24 (wow, lots of confidence in my skills!) and they were going to tell her I was dead but instead they asked why the box in her carryon had so many wires in it. She realized they had prayed the pants and busted out laughing which didn't exactly impress the screeners until she told them what she had and they got excited about seeing them and talking about the WWII stuff.
Still can't believe she thought I had crashed.....