What's this old movie called?

when i was around 7 years old i remember watching this movie where people went back (and maybe foward) in time and there were also flying meatball-like creatures in it. i dont remember their purpose but they were big creatures and they could eat through steel and stuff. when those people were traveling in time, the world was completely empty from people so they could go inside the stores and stuff and take whatever they wanted. oh, and i think the film also had something to do with airplanes