Why didn't the four generations of Naruto teach Flying Raytheon to talented ninjas like Kakashi?

First of all, Namikaze Minato and Kakashi are very different in chakras in essence. Watergate chakra has the attributes of wind, while Kakashi chakra has the attributes of earth and thunder, so it was impossible to learn at that time. Even if Kakashi became a tolerant chakra who mastered the attributes of wind, fire, water, earth and thunder, it was only after Namikaze Minato's sacrifice that he got sharingan with the attribute of earth, so he could not learn to fly Raytheon in essence.

At the same time, Kakashi, who got Shalingen, was immersed in the sadness after "death" with the soil, and after killing the last teammate Lin under the pressure of Shuiren, he himself fell into endless remorse and remorse, thinking that he was not worthy to be a ninja, and no matter how clean his hands, he could not get rid of the invisible evil. At that time, Kakashi was self-hating and had no desire for self-improvement. If Maito Gai didn't greet him every day, I'm afraid he would.

In addition, there were four generations of Huoying Shadow Guards around Namikaze Minato at that time, and the situation was similar. Shiranui Genma, Yanxi Tatami, Hagane Kotetsu, Kamizuki Izumo and others, even though Namikaze Minato is called Yellow Flash, he can't take care of multiple battlefields at the same time. He must build a shadow guard and teach them the same abilities as himself and how to support the battlefield faster.

In the forbearing world war at that time, Watergate could think of only one way to take care of the battlefield at the same time. He can't and has no spare time to teach Hatake Kakashi to fly a Raytheon plane.