UFOs explained by natural phenomena says Uk report

Here's an interesting story about a study from the UKs Ministry of Defense that reports that UFOs can be explained by natural phenomena, I,ve seen some strange things in the sky and I would tend to agree with that apart from one statement,

"and possibly some other less-known effects, are responsible for some unidentified aerial phenomena. - reuters.com"

This to me seems like an out, anything that they can't explain could be put under this statement, which I guess that means there were some things they couldn't explain.

Makes the report kind of useless then, probably.