The Legend of Korra

Also something confuses me, they speak of planes as if it was the first time they see them but Iroh learns how to fly them in a few minutes? Plus they know they use airfields and need runways to take-off, not to mention that these planes are a thing Sato came up recently but they had defense against other airplanes, so he foresaw them being stolen?

I don't think it is hard to imagine that planes need some sort of runway to take off of. These people aren't stupid and considering Iroh is a General of an army, I feel like he is trained to evaluate situations. As for the device Sato made that was a defense against other planes, I did find that very bizarre. You would've thought that the Equalists would be cocky enough with all their security and power that they wouldn't need a backup system like that to take down a high jacked plane, but whatever.