I've actually found it to be the opposite in my case, after having used a double-edge safety razor for almost 7 years. When I use the DE razor, I know exactly where the blade is and it gives me greater control if I need to go over a spot again that I missed. With the disposable razor, I've always found it difficult to tell where the blades are on my skin, which makes me prone to errors. The multiple blades in sequence also make it much more nick-prone when going against the grain for a closer shave, or as in the missed-spot scenario I just mentioned.
But yes, you're right - it's basically impossible to travel with a DE razor without a checked bag. Even just carrying the handle without the blade in your carry-on is a risk. I have an acquaintance who lost his DE handle to a TSA agent that wasn't interested in understanding that the handle by itself poses no more risk than a toothbrush. So, if I'm flying, I'll suffer with the disposable razor and never shave against the grain.