I have a pair of noise-cancelling over-ear headphones that I've only ever taken once with me on a flight. They are too heavy for precious little seven-kilo carry-on luggage limits, and take up too much space.
This is why smaller lighter noise-cancelling in-ear buds are a bonus for fastidious travellers like me.
For now, you're not going to get high-quality sound with any ear buds, but the Beoplay E4 versions ($380) give solid enough sound and reasonable bass, and the noise-cancelling is unexpectedly effective.
The E4 dulls the sound of a boiling kettle, surprisingly almost as well as my partner's Bose over-ear headphones. Voices around you can still be heard, which is okay because it's the roar of a plane engine I'm interested in and these things do a great job in muffling that.
You slide a button to activate the noise-cancelling function, but it isn't instant; taking a second to kick in. Also, they're not wireless, so watching YouTube videos on your iPhone 7 is not an option.
They come in an unobtrusive matte black finish, and with the buds off centre and angled, snug and comfortable to wear.
To deliver a cleaner sound played from computers and mobile devices to headphones, try the DragonFly Black (1.2 volt) or Red (2.1 volt) digital-to-analog converter ($160 and $320). Personally, I found I had to turn the volume up to appreciate the clarity.
The DragonFly either plugs into a device's USB port or via cable adaptors for mobile phones. At 2.1 volts, the Red is compatible with a broader range of headphones. Both are small and portable, the size of a USB stick, and are software upgradeable.