[sjwright]

This is why some headphones (notably the Bose QC15) have a little hi/lo switch on the connector. When using the in-flight entertainment, set it to "lo" which attenuates all incoming sound. Then you compensate by turning up the entertainment volume.

This works because most aircraft systems deliver PA announcements at a pre-set volume and isn't affected by the entertainment volume.

(The other thing I tend to do is simply disconnect my QC15 during announcements and listen (or not) to the announcement broadcast in the cabin, attenuated by the headphone's noise cancellation.)

[nkantar]

Disconnecting numerous times throughout a long flight (e.g., LAX–LHR) is not only massively inconvenient and also repeatedly ineffective. By the time I've yanked the cord out, I've already been deafened (and scared shitless) by the beginning of the announcement.

I do like the headphone-level filtering idea, though, and might look into this for my traveling needs.