What is the most realistic heli for X-plane 11? I would love to find one that is about as good as the Huey for DCS.

 

http://store.x-plane.org/Bell-407-XP11_p_620.html

I'll second that Bell 407 payware model, it's very good.

But also check out the payware X-Trident Bell 412, with more advanced features like sling ops. This is the one I fly the most, but I also have that 407. These are the two best payware helicopters in XP right now in my opinion, and they're both updated for X-Plane version 11.

There is a free Bell 429 that is also very good, and uses (by permission) the plugin from the X-Trident 412 for the advanced features like force trim release and 3-axis autopilot.

There are many more helicopter models available, both free and payware, but make sure they're updated to XP11. The quality is hit or miss (mostly miss) on the older models at the .org. 

X-Plane's internal flight model includes realistic features like vortex ring state and retreating blade stall. Maybe not quite up to DCS quality, but I think we're supposed to be getting mast bump in XP11 for teetering twin blades like the Huey. I'm not sure it's in yet.

Thanks for the replies, I think I will try out the Bell 407 first.

 

Are there some addons that can give you heli missions or some addon scenery that is especially fitting for heli flight?

 

I don't know about helicopter missions, maybe someone else here can jump in. Here's a free scenery package for UK Oil Fields that you might want to check out; it's a challenge landing on those oil rigs:

http://forums.x-plane.org/index.php?/files/file/33880-uk-oil-fields/#comment-54683

There used to be a moving USS Perry frigate with a helipad on the back in earlier versions of XP, and you could use the "load situation" for an approach to the frigate. That situation file is missing in XP11, so I don't know if the Perry is still in there somewhere. Maybe someone else knows.