i live in chicago too! i fly a lot and i always bring my knitting with me.
i've gone in and out of midway and o'hare with needles tons of times with no problems. i use a fingernail clipper to cut my yarn.
the only time i ever had a problem was on Quantas flying back from Sydney - they made me cut the metal needles of my circs! Nobody said anything on the way to Australia, so i was totally surprised to get stopped on the way back. good thing i didn't tell them about the pair of bamboos i had stashed in the bottom of the same bag! imagine a 14 hour flight with no knitting! hellish.
knitting needles are definitely allowed if you're flying domestic (TSA makes the rules for all US airports) - but the rules are different if you're going international - so check it out beforehand.
if you're nervous, you can print out the following pdf file and bring it with you for the rare case of the tsa people giving you any guff.
maybe someday i'll be in town for a illinois get together!