Season 2 aka Knight of the Twin Moons is a 12 episode season that picks up right where Season 1 left off. With Loise and the boy from another world (Modern day Japan) , Saito.
Agnes, royal guard captain probably gets most of the character development in this season. I guess the initial concept of Familiar of Zero aka Zero no Tsukaima drew me in back in 2007 but I wanted more. The steady development of the main relationship, an evolution of Saito's ability. Just something.
The use of WW II fighter was really stretching it for me. Teenage boy knows how to make repairs to the war plane after it was just in a rough landing. Fixed it with metal and items found in a Medieval world. Sort of reminds me of "Army of Darkness" to be fair to FOZ. One was about a making a chainsaw and "boomstick" usuable while the other is about a flying hunk of metal...
My favorite episode is without a doubt, The homage/Parody to the Hollywood film, "Roman Holiday". Involving Saito and the Princess. This being Anime, just quite more ecchi and comedic in tone.
I don't think that I'll be watching season 3 or 4 any time soon due to the real lack of development in this season. A lot of setup and introducing more characters.