I flew a couple of months ago to mexico. I hadn't been on a plane in about 15 years, and I had e-cig stuff with me. I thought for sure I'd run into some sort of problem. On the TSA website, it says that all lithium batteries must be carried on the plane with you. So I did. No problems departing from Minnesota. They didn't even search my carry on bag. The juice is fine on the carry on too. It just has to be in a clear ziplock bag and each container must be 3oz or less. That shouldn't be a problem with e-liquid as the biggest bottle most people have is 30ml, which equals one ounce. I also went through security with no issues with that. It wouldn't be a bad idea to keep the labels on the bottles, so it's clearly marked whats in the bottles.
On the way back from mexico, I did get stopped in security. They noticed something suspicious in my carry on bag. The woman kept scanning it over and over again. Then she called the TSA officers over. They asked politely if they could search my bag. I agreed. I thought they were worried about the four 18350 batteries I had. I was wrong. The suspicious item turned out to be my electric toothbrush. They pulled the toothbrush out of the bag, looked at it, and he turns around and yells to the x-ray girl, "It's just a toothbrush!" He was kind of laughing too. Then I went on my way.
I think people make too big of a deal out of flying with e-cig equipment. It's really not a big deal.