About 5 or 6 people were outside the wal-mart parking lot last night, I think some of them were employees on break. I was walking to my car to put my groceries in and all of a sudden i heard this BIG rumbling noise coming from the sky. I thought it might of been some kind of aircraft and looked up to see it (please keep in mind last night was CLEAR! there was NO cloud coverage) and I didnt see a thing! I could hear a BIG craft going slowly over the parking lot. It sounded like it was RIGHT OVER us but I didnt see anything. The people on their break were also looking up at the sky and it looked like they couldnt see what it was either - but I know they all heard it. I felt a little bit warmer when it passed right above, and somehow calmer, like I wasnt scared like I was before it did. Its hard to explain it. I tried to record the sound with my cell phone but it kept turning off the whole time - no matter how many times I tried to turn it on. after it was pretty much gone all the people outside went back inside but I stayed to see if I could see what it could have been - maybe look at some lights that might come off of it and as soon as I couldnt hear it anymore I saw 2 jets racing towards whatever went over the parking lot. Around the same time I heard several sirens going West as well. Could this have been something flying towards ft. riley - which is in that direction? And if it was HOW could it have flown so slowly? It took about 3 and a half minutes for it to get just barely over Manhattan - which isnt that big of a town. Im still a little spooked and just want to know if ANYBODY else heard it?