The TSA’s Christmas Day security directive, following the Northwest flight 253 terrorism incident, with its prohibitions against passengers roaming aircraft aisles or placing blankets in their laps during a flight’s approach, was a short-term response to an emergency situation and some of its elements were widely criticized.

But, starting Jan. 4, the TSA has dug in with “long-term, sustainable security measures,” which alter the flavor of the air-traveler experience for flights inbound to the U.S. for the forseeable future.

Some of the Christmas Day mandates about in-flight prohibitions, which drew such scorn, are dropped, but remain optional prohibitions at the discretion of the airlines and pilots.