Then paratroopers had to wait for their tanks to catch up overland. Today's US Air Force can fly in the tanks too, radically changing the strategic realities of land and air war. The key piece of equipment is the Boeing C-17 Globemaster transport plane. First introduced in 1993, the C-17 can carry the 70-ton M1 Abrams main battle tank, smaller M2 Bradley tanks and even helicopters. Most importantly the C-17 can land on dirt airstrips and on short runways of 3,000 feet. Traditional transporters can do neither.

Put the C17's capabilities together and it means that the Pentagon can fly tanks into short dirt airstrips in the middle of nowhere. This means that airstrips in northern Iraq can be used, if time allows, to launch armoured attacks. The US Air Force has specialist Red Horse teams whose job is to clear and repair an airstrip rapidly, or when necessary make one from scratch. Helicopter-borne troops can seize an airfield and then, as they expand around the base, transport aircraft begin to arrive.

The C-17s can come in one after the other, like passenger planes dropping down to Heathrow. The armour they disgorge will give a hardened spine of reassurance to otherwise lightly armed parachute troops. But though transporting large numbers of tanks in this way would put too much strain even on US resources, the M1 Abrams is the undoubted king of the battlefield and only a few would give massive support to the rest of any invasion force. In 1991 the most dramatic US operation was a drive of 100 miles by Airborne forces north from Kuwait.