Star like objects moving across the sky

My wife and I were at the drive-in Friday night facing the North screen.  It was a clear night at the time and there were many stars in the sky.  
Around 10:30, I looked up and saw about 30 to 50 objects flying across the sky.  They looked like slow moving stars and were in a large cluster but in no type of formation.  They took about a minute or two to pass over.  Then several more smaller clusters of 3 or more went past over a period of 5 minutes.  My wife and I were not the only ones to witness this event.  Several other people were out of there cars looking up at them as well.