In Croatia they want you on the ground calling them to close the plan – the explanation is S&R purposes. In Slovenia you can close if while still airborn – field in sight.
Interesting. I have had at least a handful of cases recently (in very different parts of France) where ATC/FIS refused to do it. Not because they didn’t want to do it generally, but they wanted me to land first. They gave me a telephone number whilst still in the air… After landing, when doing the phone call, I ended up speaking with exactly the same person in some cases!
Ajaccio Approach were perfectly happy to close my flight plan while in the air (landing at Propriano, with the field in sight). In fact in turned out to be a while after closing it before I landed, due to parachute ops. This was this Sepetmber, just before the EuroGA fly in at Calvi.
Do you refer to the last say 18 months?
I’ve never had a problem closing a VFR flight plan in the air in France, field in sight. Except at night, when they wanted me back on the ground before they would close -which is nice and caring of them 
In France, they now don’t seem to accept it all anymore (despite their AIP saying the contrary). Anybody know why that is?
It is easy to close the fpl whilst still flying in Czech Republic and Slovakia. It is enough to say that you have the field in sight. It worked for me many times, no objections ever made by ATC.
There are several countries that let you close (not cancel) the FPL with the message ‘field in sight, landing assured’. Works well in Spain where often you land at a non-towered field close to a towered one. You’d be talking to Approach while descending to your destination. Examples would be LEMG for LEAX or LEZL for LEJU.
Achimha is right.
In Belgium, your active fpl will never be closed whilst still airborne. Phone only.
Sorry I meant closing.
