I've never heard them, so cannot really attest for their sound quality, but for $60, you can get the Etymotic MC5. I have a pair of Etymotic ER4S, and they're really great for airplanes. Some people find the triple flange tips uncomfortable, but they work great for me and I find them pretty comfortable.
http://www.amazon.com/Etymotic-Research-Isolating-In-Ear-Earphones/dp/B003S3RFIQ/ref=sr_1_1?ie=UTF8&qid=1345160638&sr=8-1&keywords=etymotic
I took a 14 hour flight to Hong Kong last December, and I brought a bunch of different IEM's with me to test, and I found the Etymotics to be the best as far as blocking out noise. My Westone 4 with Shure olive tips were surprisingly good also. I personally found this setup to be more comfortable than the Etymotics for long hours though. My customs weren't bad, but didn't block out as much as the earlier two. I also brought along a set of Ultimate Ears TF10, and they were terrible, as were the Sennheiser IE8's, which I would highly recommend AGAINST for flights.