I am not sure why she brought it on a plane, but it had to sit on her lap the entire flight!
She told me all about how she made it: She held on to a football and wrapped the entire thing in plaster. Plaster is the material that you would make a hard cast out of if you broke your arm. Then after it hardened, she had to pop the football and wiggle her hand out. Then she attached another plaster version of her arm on the other side of the football. It was a pretty cool sculpture, but I just thought it was strange to ride next to on a flight!