noimages = 4
var adImages = new Array()
for (i = 0; i < noimages; i++)
{	
	number = i + 1
	adImages[i] = ('images/aircraft/' + number + '.gif')
}
thisAd = Math.floor(Math.random()*(noimages))
setTimeout("rotate()", 1000)
function rotate() 
{
	if (document.images) 
	{
		thisAd++
		if (thisAd == noimages) 
		{
			thisAd = 0
		}
		document.aircraft.src=adImages[thisAd]
		setTimeout("rotate()", 30000)
	}
}