>>715311878
see
>>715309759
they had superior launch ability due to being able to use their arms
They could also take off from water

the massive pterosaurs like quetzalcoatlus had a weird lifestyle that birds literally cannot do, where they hunted primarily on the ground as agile quadruped hunters, then took off and flew hundreds of miles away when the local prey was depleted
They could do this because they could use their flight muscles for takeoff and land locomotion