strange flying insect,anyone know what it could be

Maybug aka Cockchafers

Dragonfly sounds most likely. You don’t get cicadas do you ? They are very large. Maybe one came over from my side of the world. They are very loud in Summer.

Horsefly?

Maybe a hawk moth of some kind. Hummingbird hawk moths have been flying around on warmer days.

OldFrill , could be that because I know it was flying, but I couldn't see it's wings

A type of dragonfly or damselfly maybe. They can be coloured but commonly brown and can have translucent wings so hard to see. I love them.

There are millions of insects so without a description will be impossible to say.
There was a large insect on the inside of my kitchen window the other day with a head like a hammerhead shark and a stick like body, I think a type of moth.