A bit of a daft one. Bought my mother a Yankee Candle and am meeting them in NYC on Friday. Rather short-sighted of me not to think of the security implications
This page says no to 'gel type candles' whatever they are!
This one is more like this:
http://www.jrcrafts.co.uk/usrimage/l_1003372.jpg
My suspicion is no for carry-on. Hopefully yes for checked, then I can give it to her at Xmas next month packing it in a carry on.