This thing was long approx. 200ft and thin. Silver metallic but shiny nothing like an airplane or anything I've ever seen before. We didn't get a chance to see it leave Because of an obstruction in our way but it was know where to be found after we got arround the obstruction. It made no sound and emitted no exhaust.This thing by the way was above the city of Tijuana and we were in our car trying to park on the US side. No commercial or private aircraft during this time.However there was both on our way back to the car. It was a clear hot day and it was hard to judge distance.((NUFORC Note: Date is approximate. PD))