I have taken mine and a spare cannister in my packed baggage and carry on baggage multiple times on Air NZ, Qantas, Fijian Airways, Emirates and Lan Chile
It has the same cannister that they have under every seat on the plane.
I once found a search form in the bag, saying my bag was searched, they had not unzipped the vest to get to the actual cannister, so must of been happy when they realized it was a life jacket.