[RugnirViking]

I fly quite a lot and have never seen this? mostly norwegian, SAS easyjet and ryanair. Is it a US thing?

I'll definitely be on the lookout next time I fly though but yeah. Maybe its not every window?

[willvarfar]

I've always noticed and wondered, so I guess it's easy to overlook but it's there.

[iSnow]

Then you overlooked it, every passenger jet of a certain size (say A320 and up) has them

[peterpost2]

Ryanair and sas definitely have them