Spotify offers lossless now. But before that the highest quality was 320 kbps AAC, and if you’re able to differentiate between that and lossless even on state of the art equipment under perfect conditions, for the vast majority of songs, you’re an extreme outlier (and in that case, sure - go for the lossless option)

You can also download up to 10,000 songs per device for offline use, which should be enough for a plane ride

I can see other issues one might have with Spotify, but I don’t really think those are among them. I’ve had it for about 15 years, and I’ve been consistently happy with it for my own use