Translation:Put on the belt.
Yeah, I paid specific attention on the plane last week, and they used 안전벨트. It seems to be more common for sure.
Nevertheless, always good to learn alternatives, were it only to be able to recognize it in written form.
안전 벨트 is a seatbelt in some sort of vehicle, whereas 허리띠 is a belt. In the translation of the sentence, it should be wear your belt since a belt is an accessory, therefore making "put on" not as accurate as "wear" would be.
This uses 매다, to tie, i.e. Tie your belt. I believe this implies a more traditional belt.
It should be wear your belt.