Depends on the woodpecker!
Green woodpecker is also known as a
yaffle, because that's one of the sounds it makes.
Great spotted woodpecker is much less noisy; you're much more likely to hear them drumming than calling.
They all make short, high-pitched squeaks or squawks, and they all fly in swoops, folding wings, then flapping for a bit, then folding again. The drumming is diagnostic as well; they drum in different rhythms. Great spot drums in machine-gun bursts of constant volume; lesser spot drums with what musicians call a sforzando. Green doesn't really drum, just makes random pecking noises.
There's also middle spot in Britain (rare). In Europe, there's also black woodpecker, a monster of a bird that pecks holes in telegraph poles, very like a great spot only more so.
In the hand, they all scream deafeningly.
Which one do you think you've heard?