Sony Stereo Headphones ($15)
These headphones are comfortable and great for plane rides, and have lasted me throughout many travel excursions including backpacking Europe, and still work perfectly. And they are $15 – which is out of control. If you forget them on the plane or at your hotel, you can easily just get another pair no problamo. But don't take my word for it – there are over 6,000 reviews on Amazon, so you know this shit is for real.
See product on Amazon