So I own the Bose QC35 and I used them a couple of weeks ago when I was on a ~2 hour flight and in a really cheap 'orrible hotel I knew already with clanky bangy noises.
I see the Soundcore NC curve and it seems to be counter to what you want.
What you need to reduce is not voice. Voice is your safety, it is a person telling you something important. You do need to reduce the lower frequencies of engine noises on aircraft, and you do need to reduce the higher screeching noises.
I have 3 journeys in next months, a short one and I am using the Slim+ when moving, the Life for hotel life. A longer one where I have 25 hours in the air and I was going to use Bose QC35 for the flights and then likely Slim+ for walking, and then a longer off-grid trip and solar with wired buds (Phillips probably).
Why would I buy Soundcore Space NC?