✓·You should follow the rules.
✓·You should have preparation.
✓✓·You must wear a special custome.
✓✓·You must keep calm when you are on the air.
X·You shouldn't jump before the moument.
X·You shouldn't wear glasses.
XX·You mustn't throw your buddies of the plane
XX·You musn't throw objects when you're on the plane