You know the cards in your seatpocket in an airplane ? Yeah that's a safety card. It shows you where ad how to exit he aircraft in an emergency, how to put on your life jacket and an oxygen mask. A safety card basically summarizes everything you learn about the aircraft in a safety briefing (safety video).
Now you ask me why people collect safety cards. Well that's pretty easy to explain:
Every airline has it's own design and a specified card for each aircraft type in their fleet. Sometimes there are even different versions active (e.g. United). So it's basically like collecting stamps...but cooler.
My first ever Safety Card was an US Airways A320 safety card and from that point my collection grew bigger and bigger. I now own over 160 different safety cards.
If you want to trade cards, just contact me.