There are about 350 men aboard the Normandy. If it was there conducting training exercises with a complement of other ships and subs, that number goes up dramatically. No one out of that entire group put 2 and 2 together and noticed that within seconds of firing a missile of any kind an airliner was reported crashed with some claiming it was hit by a missile? Or all of them were threatened and remain sufficiently frightened that not a one has stepped forward?
I agree with your thoughts. No way on earth you can keep that many people quiet.