Indoor cat frantic to go out

I read the previous thread where the female cat was frantic to get out. My neutered male cat is about 10 months old and always wants to go out, especially if we are outside. However, we built a 300 sq ft enclosure for them about 2 months ago. Recently he seems desperate to get out again. It's torture to get out the door to walk the dog, because Tig is trying to get out too and we have had to chase him through the bushes a few times! But I have found it escalating in the last week or so. Is there a reason, like a female in heat? Would this affect him even though he's neutered?

I don't mind walking him on leash but he fights when I try to put on the collar and really, you'd think he'd enjoy his new playground! do they ever grow out of this?

He's testing you. If you let him out just once, he's alway going to beg to get out. You might want to just put him in a room when you have to walk the dog, so you don't have to be so careful at the door.