UFO Spawn rate
Its been pretty random for me. The first few days I saw none. Then other days I saw more than I had ammo. It should balance itself out.
Forum Discussion
I usually see a UFO at least one of every four towns I visit. I just visited about 20 friends and used all 6 of the ammo I had. I saw at least four ufos once I ran out of ammo. Ironically I purchased donuts today.
