It is likely that many airlines will cut some routes, freeze recruiting and not replace retirements until the war is over and some idea of future trends is available. Some will, as after 9/11, actively reduce staffing levels - which may cause problems in the probable post-war recovery.
The war is likely to be a bit longer than many of us assumed, and the effects on airlines will be correspondingly larger. How much larger is anyone's guess, and individual airlines will be more or less pessimistic than me. I don't believe that we are on the edge of an aviation disaster, but some airlines may do and will react accordingly.
I didn't hear of BA's plans, but what you say would not surprise me.
Scroggs