And here's the main reason I don't think it was the hijackers (at least not alone.) Remember the morning of 9/11, as the reporters and the firemen and the police officers in New York were reporting on all networks "huge explosions," multiple explosions, secondary devices? I remember it well. It's all on the web for us to watch again.
It's true that many people described hearing "explosions." at the WTC on that day. Most of those accounts are about the sound of the towers as they were collapsing, and some are about cars, trucks, etc. that were on fire after the collapses.
However, other accounts describe events
before the collapses. For example:
Monchery, Alwish (E.M.T. E.M.S.):
"Sound of popping and exploding."
Murphy, Keith (FDNY):
"Sounded like bombs."
Burns, William (Lt. PAPD):
"Explosions."
Terranova, Rosario (Lieutenant E.M.S.):
"Kept hearing these large boom, boom."
Fitzgerald, Anthony (Lt. PAPD):
"Sounded like explosions."
Rodriguez, Andrew (PAPD):
"Under the assumption that the sounds were secondary bombs."
Meier, Mark (P.O. PAPD):
"Like a shotgun going off."
Barriere, Wilfred (Det. PAPD):
"Sounded like explosions."
Smiouskas, Richard (Lieutenant FDNY):
"Like explosions."
Murray, John (Fire Marshall FDNY):
"Sounded like bombs, like blockbusters."
All of the descriptions above are of bodies from the towers hitting the ground or other structures.
So, yes, many people did describe explosions, and conspiracy theorists always take these descriptions out of context. These posts of mine should help you to understand the context of these descriptions:
What they actually described hearing in and around the towers
Descriptions of the north tower elevator shaft, lobby, and basement jet fuel explosion
I hope this will help you to understand that there are rational explanations for what you feel is that strongest evidence against suicide hijacker involvement.