British Airways flies planes empty because it lacks flight attendants

British Airways has admitted flying dozens of "ghost flights" across the
Atlantic, with only pilots and cargo aboard (and no passengers), because it
doesn't have the crews to staff the flights with passengers:

http://www.emailthis.clickability.co...5276864& pt=Y

Some of the ghost flights are apparently flown just to keep slots at major
airports active, even though every ghost flight burns tons of fuel.

Why don't they just hire more FAs? Or--like several other airlines--do they
make so much from hauling cargo across the Atlantic that they don't need
passengers to turn a profit?