For all the US flights, the cockpit is locked at ALL times. If the door needs to be open for any reason, the food cart is used to block the access from the cabin while one or two stewardresses stand in front of it. I assume this is not the case with non-US airlines hence the “surprising” comments here. If the airlines go through all that trouble to protect the locked door it means LAND THE PLANE at all costs. It does feel safer to see this being practiced…which i’m sure the next terrorist act involving vehicles is going to be very different and may not even be airlines anymore.