So let's start backwards. A Metal Band is generally not going to be the best place for accurate conveyance of historical information. If you are looking to learn more about the Night Witches, I would recommend "Wings, Women, and War: Soviet Airwomen in World War II Combat" by Reina Pennington as the best work to look to for Soviet aviatrix during the war. "Soviet Women on the Frontline in the Second World War" by Roger D. Marwick & Euridice Charon Cardona, and "Soviet Women in Combat: A History of Violence on the Eastern Front" by Anna Krylova cover women in the Soviet military more generally, but devote a good amount of coverage to their involvement in aviation.

Now, as for your actual question... well, to get to the point, let's rephrase it. "Why would the Night Witches be taught in school in the US?" Yes, they are one of those interesting little stories from history, but what purpose would a unit on them serve as part of a high school education? The College Board site on AP European History provides several sample syllabuses, which I'm refering to here.

In Sample I, in "Unit VIII: A Time of Tragedy and Triumph, 1938 – 2010", World War II in its entirety is summed up as "2) Major events of World War II" and "3) Nazi policies on race and conquered territories - a. Holocaust". Sample III actually just skips from the Interwar Period to the Cold War. IV is a little more verbose, but still is looking at broad themes like "Considering the period 1933 to 1945, analyze the economic, diplomatic, and military reasons for Germany’s defeat in the Second World War", which is also echoed by II.

So anyways, my point here is, how does the Night Witches fit into our understanding of the war as a Macro event? Because that is the level of coverage that you'll get in a high school history class. You're expected to learn history in the broad strokes. They would make for an excellent topic of an individual research project, but there is no reason to cover them, specifically, as a focus of a lecture, or even in passing. Even if a syllabus were to go so far as to spend time on gender roles in the Soviet military during the war, I would still be surprised if they were too focused on, as they were something of an anomaly, which makes them a rather poor focus for such a learning unit.

So anyways, you could come up with 1,000 interesting stories from history, none of which are taught in school, and every single one of those you could ask the same question about, and the answer will kind of be the same. Why is any particular one more worthy than the other? How does any particular micro-event contribute to our broader understanding of history? Or put more simply... "we only have so many classes to teach you roughly 550 years worth of European history, so I'm not going to waste it on telling cool stories all the time".^1

1: Related side note, my AP Euro teacher did waste it telling cool stories all the time, and we hadn't even gotten to Napoleon by the time of the AP test, so....