> air can be safely leaked in emergency

Not if it ruptures.

https://www.space.com/space-exploration/launches-spacecraft/...

SpaceX lost four spacecraft this way.

A large amount of air that wants to go somewhere fast causes humans serious troubles. https://en.wikipedia.org/wiki/Byford_Dolphin

"Investigation by forensic pathologists determined that Hellevik, being exposed to the highest pressure gradient and in the process of moving to secure the inner door, was forced through the crescent-shaped opening measuring 60 centimetres (24 in) long created by the jammed interior trunk door. With the escaping air and pressure, gross dismemberment ensued; it included bisection of his thoracoabdominal cavity, which resulted in fragmentation of his body, followed by expulsion of all of the internal organs of his chest and abdomen, except the trachea and a section of small intestine. These were projected some distance from the bell, with one section being found 10 metres (30 ft) vertically above the exterior pressure door."

It will yeet you, and you weigh a lot less than the flying car does.

This is enough pressure to launch a car and flip it in the air, you can't just "safely leak" it at any useful rate of speed in an emergency. In an emergency it will rapidly explode.