I'd phone the airline and make sure it can go in the cabin. I've never had a problem flying with my fiddle, and I have flown with a double fiddle case which still fits in the over head bins. I've flown low cost airlines with fiddles before and never had a problem although I've flown Ryan Air so can't offer advise with them other than to phone the company direct for advice.

I wouldn't put the fiddle in the hold unless you have a very good case. Most airports will send instruments through as fragile and oversized baggage labelling it clearly but it is up to you as to whether you take the risk of putting your fiddle in the hold. If you have a strong case so the fiddle is well protected there shouldn't be a problem with putting it in the hold.

Best of luck with your trip. Safe journey.

Khatt