It was the 4th of July in Yankton South Dakota and the usual celebration of partying known River Boat Days was going on the southern part of the city. There was a fireworks display set off around 9:00PM south across the river, probably only a quarter mile away, on the Nebraska border for everyone to enjoy at the River Boat Day celebration. I was standing with hundreds of people watching fireworks being set off and enjoying what we were all seeing. As we were standing there looking to the south, I noticed the full moon that night that was a bit farther to the right in the sky than the fireworks were going off in. I was distracted briefly when I noticed what looked to be two huge cigar shapes close to one another (one slightly ahead of the other) traveling together what appeared to be between the moon and earth in space going from left to right. They were long huge dark cigar shapes that were very evident with the moon behind them. It took about 10 seconds for them to pass in front of the moon, and by the time they had passed hundreds of people were pointing at the moon and clarifying what I had saw. What ever we all saw were huge, and they definitely were in space as all they appeared to be were 2 very long and huge silhouettes going across our moon visual in space. I could draw a picture of the way this looked any time.