Your problem is that you're using elif and if statements. As soon as one of your statements is true, the other ones don't run. You need to use multiple if statements instead of the elif and else statements. For instance:
car_year = int(input())
if car_year <= 1969:
print('Few Safety features.')
if car_year >=1970:
print('Probably has seat belts.')
if car_year >= 1990:
print('Probably has antilock brakes.')
if car_year >= 2000:
print('Probably has airbags.')
I wrote my code in python 3.8. I hope this helps.