(Edit: purely illustrative rhetorical question, but I appreciate the responses)
So you can keep your animal proteins: it'll just be eggs, fish, poultry, and pork.
For business trips, the choice is between two hours and two days, and unfortunately my body goes haywire if I don't eat some meat at least a couple of days per week (talking about 200g/300g total though. Not kilos of it).
On the other hand, I'd happily take trains as more high speed lines open in my country, and reduce meat consumption to bare minimum my body can tolerate.
For personal transportation, going fully electric won't be possible due to my circumstances, but I'd happily switch to a hybrid which would convert 75% of my in-city travel to electric (which I'm actively planning to do).
I also work on projects which tries to reduce footprint of data centers and computation, so there's that.
Isn't this just a nutrient deficiency in whatever you were eating instead of meat? Meat is "convenient" because it's high in a wide variety of minerals, vitamins, essential amino acids, etc. that your body can't make. (The animals mostly can't make them either but guess what livestock eats.) There are plants that contain each of them, but few if any that contain all of them, and then if you're missing one you're going to have a bad time. So the problem there is almost certainly that you need to eat some different plants than that the thing you were missing is only found in animals.
There are ethnic populations that have reduced capacity to efficiently metabolize some plant-based diets due to thousands of years of selection pressure (or lack thereof). A diverse plant-based diet won't kill them, they simply lack the enzymes to have a good experience with it because for thousands of years they had little use for those genes.
It is a relatively small population globally, as it tends to coincide with regions that weren't conducive to supporting large populations thousands of years ago. The current distribution has significant overlap with the developed world though.
I have to imagine that someone with meat-adapted genetics is going to suffer quality of life issues on a purely plant-based diet. Everyone has a set of foods like that.
I eat (and like to eat) tons of veggies, yet I feel my brain capacity declines and I crave esp. meat if I don't eat it for a long time (for two weeks or whatnot). As I said, I don't need two ribeye steaks per week. My body is very good at signaling what it needs, and I prefer to listen to it.
What I eat is Mediterranean cuisine 99% of the time, and it's pretty well balanced, yet eliminating meat is not possible for me. So, my diet is not junk food peppered by meat. It's mostly veggies and legumes (beans, lentil, whatnot), peppered with meat. Yet, I need it, and this is something I tested over and over more than two decades.
On the other hand, my wife is completely opposite of me. She can go a month or so without meat. So, not every person is the same, and assuming that every human being works the same is a big mistake made by modern medicine. For example, my brain chemistry is also different and I consume B12 much more than a typical human, so I need to use B-complex supplements more.
If the plane doesn't use synthetic fuel that's a political problem that I can't realistically solve as an individual.
The methane from raising animals exists in an overall equilibrium. It isn't extractive and the total magnitude of the effects of that chemical system is comparatively minor.
