Some birds and several pterosaurs got to human masses and more. Staying in the air is not much of a problem, but launching is. Pterosaurs have a massive advanta

Some birds and several pterosaurs got to human masses and more. Staying in the air is not much of a problem, but launching is. Pterosaurs have a massive advantage here in that they launched with all four limbs, meaning they could use their flight muscles to launch. Birds can't do this and have to rely on their legs (which are useless in the air).