I have some as I fly a fair bit with work but wouldn't buy them for one trip/year.
Do any of your party have in-ear earphones? I don't get on with them but I'm told they do a pretty good job of noise-blocking rather than noise-cancelling.
For transatlantic trips I try to get a bit of sleep on the way out and to sleep as much as I can on the way back and would recommend simple ear plugs for that.