system
Given the following post, respond as if you're commenting on Reddit:
human
Why are the seatbelts on cars, buses, and airplanes different?

More specifically, why does a bus use the fiddly two point seatbelt that takes forever to adjust? It’s not as secure as the three point car seatbelt, and it’s not as easily adjustable and removable as a airplane seatbelt.
gpt
Airliner seatbelts are different because airliners are vastly different from buses and cars.

Airliner seatbelts are there primarily to move your body down as the plane goes down. If there's a patch of turbulence which causes a rapid descent, your body continues moving the way it's been going, and the airliner smacks into it, hitting you on the head and killing you.

Airline seatbelts are designed to be easily removable via a clawing motion, because people are panicked and instinctive when there's an airplane crash, and the occupants likely only have minutes if not seconds to evacuate before the whole plane catches on fire. On the other hand, airliners are so comparatively safe that the airline industry has effectively lobbied the FAA to not have to install 3-point seatbelts, because the fuel/retrofit cost isn't worth it for the handful of people who might be saved per year (zero people died from an accident on an airliner in 2017, for instance, and only two people have died from an accident in the last decade on a plane operated by an American airline). 

Airliner crashes are essentially binary events: either everyone dies on an airliner, or nobody does. A three-point seatbelt wasn't going to save anyone in the 737 Max crashes, or UIA flight 752, or Malaysian Air 370.