What is my earliest memory? Why has it stayed with me?

Again, another question that makes me think...
I think my earliest memory is of flying on a plane when I was 5 years old. I remember getting this little "wing" pin to wear, and I was so proud of them. I don't remember much else about it, other than holding someone's hand (come to find out later, it was my sister's).
I have some other memories that seem early, but I am not sure of the timeline on those, but I think this is the earliest. I think it has stayed with me because it was so exciting at the time. I think I felt really special then, and so I remember it.