Passengers on US flights will soon be allowed to carry small knives for the first time since the 9/11 attacks.
An announcement by the American Transport Security Administration (TSA) also allows hockey sticks, snooker cues and a maximum of two golf clubs to be carried on board from April 25.
The TSA said the relaxation would bring the United States into line with the rest of the world - but cabin crew are furious, with unions saying their members will be put in danger.
The Association of Professional Flight Attendants asked the TSA to reconsider, and "categorically rejected" allowing knives on board.
And the Flight Attendants' Union Coalition said: "As the last line of defence in the cabin and key aviation partners, we believe that these proposed changes will further endanger the lives of all flight attendants and the passengers we work so hard to keep safe and secure.
The airline industry claims beefed-up security introduced in the aftermath of the 9/11 terrorist attacks have cost the industry £4.6 billion.
The TSA said it was a "risk-based approach" which would allow baggage handlers to focus on hunting for more dangerous items like explosives.
But it drew the line at full-size baseball and cricket bats, which remain banned, along with razor blades and box cutters.