A gasoline tanker and bomb would make a fire. As with any other vehicles on the road, they crash and catch fire on a regular basis without taking down sky scrapers.
Hollywood representations of what gas tanks do when ruptured are inaccurate.
Yes, from a plane, which first made massive holes in the structure, followed up by the fuel from an airline that carries more than one tanker truck worth of fuel being deposited into the center of the building.
Good luck getting a tanker truck into a modern skyscraper's lobby. They've all got anti-truck posts concreted in around the perimeter to prevent just that.
Hollywood representations of what gas tanks do when ruptured are inaccurate.