While the industry as a whole will suffer because of this, there is no way that the airlines will all face "the end." That defies basic laws of supply and demand. There is still demand for air travel. Granted, now the leisure market will dry up for a while, but it will be back to normal (I think.) Business travelers must still get from point A to point B.
As of this post, I do not know if the Federal Government will provide some money to aid the airlines. Even if they do not, some airlines are in a good enough financial situation to get through this tough time.
We will probably see some airlines that have a hard time (but many of them were having a hard time prior to the terrible terrorist attack.) But I don't think this is the end of the world (literally and in figurative airline terminology.)