The biggest thing I kept lamenting all through my reading of this book is the distance between the reader and Katya, and between Katya and her world. I was getting zero emotional resonance. There was lots of telling rather than showing, from Katya's drive and motivation to be a pilot (she identifies her father more regularly as a university prof and violin player more than pilot) to how hard the girls study (always studying...what, exactly?) to the deaths of her various sisters-in-arms (the first pair of deaths was a couple of women who had been mentioned only once or twice, pages and pages ago). I felt like we were just drifting through her life, a tale told long in retrospect when the setting needed to be in-your-face and urgent. [There are a few statements that might be considered SPOILERS in the review that follows. I have not marked them because a)they're relatively small, and b)this is not a subtle tale of nuance and shock and surprise.]
It's not even clear to me how/when Katya gets to pilot! They spoke of their academy graduation as "earning their wings," but she's only ever shown working as a navigator. In the war? Navigator. She finally pilots near the end, and she waxes poetic on the beauty of the night sky, but I was just wondering how she was qualified to be flying that bird since I can't recall her ever piloting before -- even in a supervised training scenario, she was so gaga over flying, that seems like it would have been a huge fulfilling moment for her. You know, complete with poetic descriptions of the sky so it'd be hard to miss. Weird.
Second place peeve is a tie between how sickeningly saccharine every scene between Katya and Vanya is (my love! Darling! My Vanya!) and the tendency (at least in the first half of the book) to have the male chauvinists all be ugly. Katya describes his yellow teeth or that guy's weak chin or this dude's "walrus mustache." Vanya? Gorgeous, and the first to show her respect.
This sappy Vanya adoration combines with the told-not-shown drive to be a pilot in how their relationship upgrades. Katya initially wants to stop after one date because Priorities. Obviously that doesn't stop it all together, and ultimately the two elope. It's only after they're married that Katya thinks to wonder if their marriage would impact her eligibility to fly. That is not the mindset of a driven, determined, and professional woman!
There is occasionally a heavy hand with some faux feminism/hypocrisy: weighing on my mind is an example towards the end. Katya seethes quietly when a male character clucks over another woman traveling some distance by herself. A few pages later, her own mother cautions Katya about being careful when out alone, which Katya shockingly realizes is good advice, especially since she didn't have a service weapon anymore. Throughout, other female characters are torn down in order to make Katya look stronger, wiser, braver (see also: my comment below about her being a judgemental priss and how the narrative always suggests she is the correct one). E.g. lecturing her friend about being friendly to the squad when said friend is the only one of the two of them who bothered to meet the other women and learn their names.
Despite all that, Katya still ultimately settled down to a domestic life. Her entire thing early in the book was all be a pilot, be good, be better than good so they can't deny you. She says she taught at an aviation school (again I wonder at her qualifications -- ambiguous actual pilot experience, limited anyway to training craft and leftover WW1 planes) but preferred to stick to her nest. She's set up with husband and kids and later grandkids, and though the author notes say she wanted Katya to be true to herself etc about seeing the world, it doesn't sound like she saw more than France! Now, in and of itself, that's all fine. I just think it's a sappy cop-out. She fits herself into someone else's life/family (a man/widower) rather than building one for herself that then included a man/family. And she just meh, gets bored of aviation after a few years, just like that? She had some PTSD-- it only would have taken a sentence or two for her war experiences and deaths endured to have sapped all the joy of it (not that that would be great messaging either, but it's all in the delivery).
Another gripe: Katya is kind of a judgmental priss, and the narrative always takes her side. Most annoying example: the character Oksana is described as cold, joyless, kinda priggish. She's pragmatic, practical, and completely harbors zero illusions about warfare and their role in it. The early part of the book heavily hints (and then confirms) that unlike the rest of them, she had already seen the ravages of war up close. Also, she's just a more reserved person -- as a non-people-person myself, I get it. Oksana's my girl. So far so good. But! BUT! Later! Katya is deciding that Oksana's personality was a "churlish mask" that she used to hide/displace her grief (and really Katya should have reached out more). No! That's not at all what was indicated! You completely misunderstood her in this moment that's supposed to show you understanding and further appreciating Oksana!
Further, due to all the other moments characters popped in to "hear hear!" Katya's advice or interpretation of a situation (sometimes actually naive or hypocritical, sometimes just equally good to the opposition's argument), there's not a precedent to suggest that's supposed to be a deliberate moment of misunderstanding. Later, Katya has a thought that she hoped the "joyless Oksana" would have enjoyed something, and again -- no! Not after we've seen her be human and even pleased aaaargh. You do not deserve to name any children after her, Katya.
Anyway, in short: predictable characterization, no emotional intensity, occasional mild hallmarks of Mary Sue-ism around the protagonist.