1) Noise-cancelling headphones for premium-class passengers;
2) General headphones, particularly for coach passengers.
This could be evaluated on the basis of comfort (ear bud vs. behind-the-ear), ability for music/sound to pass through, the ability to help block out sounds from the airplane (i.e. crying baby, jet engines, etc.), durability (how long it lasts), whether it's worth the value (on airlines where you have to pay for the headphones), and/or other factors.
Thanks for your thoughts!
Soxfan
