Manzi flying... ummm, I mean walking

I took Manzi out to fly yesterday. I used his leg leash. He was very excited to go outside and held his wings out while walking to the open field. I set him on the grass and had him fly to me. He made a couple of those flights. Then I decided to send him out from me, have him fly around, then come back. He has done this successfully several times in the recent past without reaching the end of the leash (it is a long fishing line).
I sent Manzi out, he began to circle around, but then reached the end of the leash (I had it a bit shorter than normal since we were in a different field with trees nearby), which caused him to fly in a circle around me. He couldn't make the turn to come back in towards me and continued in a very large circle. He tired out pretty quickly and landed on the grass.
I called him back to me and he didn't come. So I sat down and proceeded to eat my lunch. Manzi seemed upset and chewed on the leg leash. After about 10 minutes of us ignoring each other, Manzi began to run (yes, with his little legs) towards me. It took him another 5 minutes to reach me! He refused to fly, except the last 30 feet when he finally flew to my hand. I realized that Manzi must have been pretty scared when he did the circle flights and emergency landed in the grass. Sometimes I forget that he can be very sensitive. Because he wasn't happy with his last flight, he was hesitant to try it again and preferred to walk, which isn't an easy task for a parrot in thick grass. In the past, Manzi has gone really high up in a tree refusing to come down. Then he'll try, but miss me and go up in another tree. I thought Manzi was being a bit stubborn, or happy in the tree. It must be that Manzi is scared of his misses and hesitant to try again. This only happened when Manzi would first start to free fly outside. It has been a long time since he's free flown though, so he must be lacking confidence.
I am afraid to fly him without the leash with our winter coming on. We're already getting nights below freezing. I had hoped that I could free fly Manzi this summer since he has been doing so well with his recalls, but now I don't think that is going to happen.