Among thousands of UFO cases, these 3 are considered significant than the rest because of the following reasons:
- All three were sighted by experienced pilots (WW2 Veterans)
- All three UFOs were reported to be fast moving metallic objects having no resemblance with any kind of known air craft, weather balloon or natural phenomena.
- In first two cases, the pilots actually chased the UFOs. The explanation of the third case were in favor of Extraterrestrial Hypothesis which made the Govt. to replace PROJECT SIGN with Project Grudge.