Well the trucks come from various sources. First would be the spoils of war. As noted previously the lady golfers aka Iraqi Army have abandoned enough arms and ammunition to outfit an army. Namely ISIS.

Second, outright theft. IF someone from ISIS sees a truck, they just take it. Doesn't matter if it's a police vehicle, government vehicle, or privately owned. Grab the keys and go.

Third stolen vehicles from outside Iraq/Syria. About 4-5 months ago a guy from Texas saw his stolen company vehicle the nightly news being driven by ISIS in Iraq. It still had his company signage on the side door!

Fourth, straw buyers. People going to Saudi Arabia, Lebanon, Jordan, even Iran to buy trucks for cash. ISIS give you a couple hundred grand and says go buy us 10 trucks. After you have stolen/inherited all the trucks you can find, you need to actually buy them.

I was amazed however that this whole subject came up in the U.S. intel community as a 'priority' problem to be explained. Do they REALLY think if they figure out HOW ISIS gets its pickups, this will win the war? Geez guys, you can buy the VIN numbers from Toyota as to which ones got shipped to within 1,000 kms of Syria. See if any of them came with satnav,or OnStar, or any other cellular communication devices? IF so, guess what? You can target the vehicle, and drop a warhead on a forehead.

Problem is if Achmed takes his Hi-Lux with the mounted machine gun out to drive Achmed Jr to school, or Mrs. Achmed to the burka store, you won't bomb it.

So, maybe you need to start channeling travel routes for ISIS to make themselves a target? Start dropping hundreds of thousands of area denial land mines. Force ISIS onto fewer roads and overland routes. Place sniping teams behind the minefields to kill sappers coming out to try and clear the minefields. Maybe try surrounding stronghold cities with mines to starve people out?

Do the civilians on the internet have to think of everything?

Yeesh.

http://www.youtube.com/watch?v=NvIJvPj_pjE

Took a Gun and built a Plane around it!

That's the plane the Obama administration is trying to get rid of and it is one of the most resourceful plane in the Air Force for helping ground forces.