I think 'The Tree-cornered Hat' may actually be an opera. It has various sections such as 'The Miller's Dance' and 'The Neighbours Dance'. I remember seeing it on TV many year's ago. I also have a variable taste in Spanish and Latin American music.
Away back, I once gave the words of 'she'll be coming round the mountains when she comes' (impolite version) to two young Spanish couriers for their coach party singalongs. In return I received the words of 'Guantanamera' and 'La Bamba'. You can guess how long ago that was, as I think they were in the charts at the time!
I do indeed remember the 'Flight over Spain' series. I've tried often to find the videos on the internet, but to no avail. Unfortunately, at that time, I didn't have a video recorder. Like you, I have been unable to identify the sound track from the series, but the music often comes back into my head. Also, like you, I love the sound of the flamenco guitar. At the moment I'm listening to a classical guitar piece by Francisco Tarrega calle 'Recuerdo de la Alhambra', played by Ernesto Bitetti. Very smooth and soothing. John Williams is another favourite of mine.
Your experience with friends reminds me of similar circumstances, but the music was not flamenco. It was local folksongs of Cantabria and the Basque areas. Even to this day I can still recall most of the words of these songs. On another evening, the barowner and his son-in-law became so engrossed in their guitar playing, that everyone had to serve their own drinks and throw the money in the till! Again, there was the time when the local 'gestapo' threw us out of the bar, just for having a sing-song! This was still in the Franco era and these guys were in black uniforms and wearing dark glasses....at 3.am.! Or there was the time when the bar had no windows (it was being modernised) and the owner locked the door when he left,..... but the place was wide open. Tables and chairs were also left out on the pavement all night long. He then came with us to another bar.
Those were the days!!!!