I'll tell you how it was:
Once upon a time, just eight short months into his reign as Ultimate Ruler of America, Dubya said "It's time to make my dreams of war in the Middle East come true." He called a meeting of his cabinet and explained that he had always wanted to attack Afghanistan, and he'd figured out how to do it.
"We'll bomb the World Trade Center and use that as an excuse to invade Afghanistan," he told them.
"Wait a minute, our World Trade Center?" Colin Powell asked. "The one in New York?"
"No, you fool," retorted Dubya. "The one in Argenstralia. Of course our World Trade Center."
Well, there were a few members of the Cabinet who didn't think that was such a hot idea, but Dubya got his friends in the Illuminati to help him out and the dissenters were all quickly brought into line.
They called the Pentagon on a secure line and got the CIA and the FBI involved too, and soon all the buildings of the World Trade Center were secretly wired with explosives during the Labor Day holiday when the buildings were all completely empty and no one was around to see.
Dubya rubbed his hands together and cackled with glee. "Soon I'll be the ruler of Afghanistan," he crowed, "and then maybe I'll try for Iraq, because they have OIL!" wang Cheney put Halliburton on alert.
At the last minute, someone realized that no one would believe the "terrorists" would be able to wire so many floors of so many buildings with explosives without getting caught.
"What will we do?" Dubya wailed. "My great imperial push to annex Afghanistan and Iraq and make them the 51st and 52nd states is in jeopardy! How will I ever become the world emperor?"
"Don't worry, Mr. President," Donald Rumsfeld told him. "I know how to fix it."
He got some planes and painted them up to look like regular jetliners, except for the missile pods, which he left on the planes. Then he chose some flights that could be conveniently "diverted."
On the morning of September 11, all the people who were supposed to fly on those fateful flights were rounded up and killed, and when the airlines weren't looking, their planes were stolen and replaced with the government's empty planes. Then the "hijacked" planes were flown by kamikaze pilots to New York and Washington and crashed into the buildings just as Dubya's minions set off the explosives in the two main towers. They waited a few days for WTC 7, because they didn't want to raise anyone's suspicions.
Unfortunately, one of the kamikaze pilots lost his nerve and crashed into a field in Pennsylvania instead, but the government boys were right on top of things, (despite the confusion caused when they crashed the Pentagon plane into themselves) and didn't trigger the explosives in the Capitol building, where the fourth plane was supposed to go.
"Whew!" said Dubya later. "Well, three out of four ain't bad. Good enough to get me Afghanistan, anyway. I just wish we'd managed to take out Congress. It would have made my job a lot easier. Someone remember to remove all the explosives in the Capitol and the other WTC buildings tonight when everyone goes home, because there will probably be a lot of bomb-sniffing going on tomorrow."
"No problem, sir," said the Army chief. "I'll have a team of guys stop by and pick them up tonight on their way back to the base."
And to this day, no one has leaked a single word to the press, the single most amazing part of this entire story.