From what I understand, and this is coming from my DM who told me, not giving a 2-week notice is not a black mark on your record but it is frowned upon. So it won't ruin your chances of getting hired with another carrier.
I have been on the other side of the desk. Used to ask prospects in the interview, who were currently employed if they could start the next week. If they said yes they didn't get the job.
My brother was looking for a driver last fall and called an ad on the net. The guy that answered the phone said that the ad was his roommates and he wasn't in but HE might be interested. My brother asked "Are you looking for work?" the guy said "I have a job driving now but if you're paying more I'll quit and come work for you". My brother asked his name and he gave it, then my brother told him "good, I'll write that down so if you are ever looking for work I'll know not to hire you" and hung up.
and by the same token, some would hire a person on the spot, and WANT THEM to start today, right his minute, or asap. just because you wouldn't hire someone, doesn't mean the 27,000 other employers will not.
But, then again, it's an 11 year old post, so I'm certain the statute of limitations has run out on the case.....