The best razor and the greenest by far is a straight razor. I use one made in Germany over 100 years ago. It’s got at least another 100 years of life left. The learning curve is steep, particularly honing and stropping, but by far gives the best shave. The only problem is the TSA.....

I've been using a Merkur 34C for 5+ years and been on a rotational schedule with it for over 3 years.
I've only been queried on it twice, when I used to bring my toiletries kit with me through security, in my backpack.

One time, TSA couldn't even figure out what it was. I told them it was a razor (didn't have a blade installed) and they were cool with my explanation.
The second time they thought it was a mining, or rock shaping tool, as if I were Andy Dufresne.