been birds, except for a slight trail of black smoke.

But by 3.25 p.m. there was no doubt. And the throbbing of the engines above was loud enough to make you cover your ears.

The first wave of EA-6B jets screamed over the runway at around 450 knots an hour.

They swooped like giant birds of prey from the same direction, with mysterious lights flickering.

To those at ground level, the pretence was the US Naval Air Station at St.

David's was under attack.

And, without doubt, the sheer roar of the aircraft 500ft above did contain an element of terror.

The planes zoomed into view in waves of four -- after the EA-6Bs came the AV-8 Harriers, and then the F/A-18s.

They swept over the sunlit runway, before making a vertical climb and disappearing.

"We are pretty much the enemy now,'' said Base spokeswoman Ens. Anne Say, getting into the spirit of things.

Not that the enemy had got things totally right. At least not according to the schedule.

Press releases had stated the action would begin at 3.15 p.m., not 3.25 p.m.

And they said it would last 30 minutes or so. In fact, after 45 minutes spectators still awaited the fourth, and last, wave.

Nevertheless for the US 2nd Marine Corps Airwing it had no doubt been a worthwhile exercise.

"It is all part of training. We are the closest Base to them,'' said Ens.

Say.

She explained the aircraft had flown some 800 miles from the US Marine Corps Air Station in Cherry Point, North Carolina.

They were refuelled on their two-hour flight by KC-130 support aircraft, and again on the return trip.

Were the aircraft armed? "Probably not, although they might have some false missiles,'' said Ens. Say.

She added: "Of course, if this was a real airstrike all the planes would have come in from different directions.''