I think it would depend on the source of the meat. If it were safely and artificially produced, there's definitely no problem with it. For natural meats (i.e. plants and animals), it mostly depends on the procurement and apparent mental status of the animal. Plants and insects are more-or-less fully ethical to eat, as they are often naturally abundant and apparently have limited if any mental activity. Humans, tending to have complex mental states, are much harder to justify. Since they have the overt capacity to refuse to be eaten (or request, in rare instances), such desires must be considered in ethical considerations. Most debatable are the common practices of cattle, pigs, etc. These animals seem to have at least minimally significant degrees of mental complexity such that we must ask the ethics of their consumption. Often, these animals are treated rather poorly in life, such that their death is a relief and release. If these were one-off incidents, eating them would not be extremely unethical, as they were already dead. However, their consumption within the capitalist encourages the same treatment of others of their kind. If "ethical" farming were practiced (here meaning ethical treatment of both animals and people, as well as more practical things like sustainability and capacity for mass-production), then it would be functionally equivalent to adding use-value onto the corpse, which is fine itself.
Now, this is just my ethical system, one to which I fall short regularly. I am something like a moral aestheticist, and do not believe in the truth of my ethics. Other people have different systems, some which I find too strict and others that disgust me in their laxness. These systems are no better than mine, but no worse except in how we judge them. It is ethically permissible for one to eat meat iff one's moral system permits or requires one to eat meat.
At least, that's my thoughts on the subject.