Classic large shape rod, looked like birds, but no flapping wings.

Classic rod. Shaped like a flock of flying birds in one line. Grey dark in colour. Flying at about forty miles per hour up an inlet from the sea and at about six feet above the water. (I was standing on the shore line looking out to sea)visability very good, summer time, mid afternoon.  No noise, no other boats ,aircraft etc in the vicinity. distance about 200yards from shore. Estimated size - 12 feet.
Had no idea what it could be at the time, but spoke to independent witness who also shared surprise and bewilderment. Saw some news on the TV in Oct 02 and realised what it must have been. Had not heard of them prieviously.
I am a surveillance expert by profession, the witness owned a hotel.
Date is approximate.  PD