Why did airline stocks fall sharply after the attacks on the U.S. on September 11, 2001?

1. The future cash flows on airline stocks were expected to increase
2. The future coupon payments (in dollars) on airline bonds were expected to stay the same
3. The future coupon rate (percentage) that investors required on airline bonds decreased
4. The future cash flows on airline stocks were expected to stay the same
5. the risk on airline stocks decreased
6. the risk on airline stocks did not change
7. the risk on airline stocks increased
8. both e and b are correct
9. both e and be are correct

j both e and c are correct