the 4 hijackers who were supposedly flying the aircraft were amateur pilots, who had learned to fly in small propeller planes, and were described by their instructors as having had only "average" or even "very poor" piloting skills. But on their first attempt at flying jet aircraft,on 9/11, these men were supposedly able to fly Boeing 757s and 767s at altitudes of tens of thousands of feet, without any assistance from air traffic control. Three of them were apparently able to successfully navigate their planes all the way to the intended targets, which they hit with pinpoint accuracy.
For such poor pilots to carry out such skilled flying would surely have been extremely unlikely, perhaps impossible.
I personally know pilots from airlines, UPS and Fedex that fly these planes. They've said there's no f'kn way they flew these planes with such precision and speed with no navigation the way they did without training on these particular jets. The report we know of is these hijackers trained on small planes and there's a substantial difference in speed, size, and weight and the maneuverability of the planes.