I've had a V.P shunt for just over a year now. I have flown at least 5 times, only 1-2 hr flights, since without any problems at all.
I've only had one flight where I had a problem...and it was my first...post-op. When I first had my V.P shunt inserted I flew home 12 days after the surgery, firstly I was scared that I would set off the metal detectors at the airport (which I didn't!!) then I was scared that those same detectors would somehow change my shunt setting (which it didn't!!). But I did end up with a shocking headache, requiring morphine for pain...but it wasn't because I had a V.P shunt...it was because I'd undergone surgery. I have to say anxiety levels for my next flight were pretty darn high, and I thought I'd never fly again...but it turned out there was no need for all the worry at all. I have no problem with flying now, and my only problem with travel now is finding enough money to get me to all the places I want to go!! I wish you all the best for a happy and safe holiday