The best-supported answer is that the hijackers of United Flight 93 were most likely aiming to crash the plane into the United States Capitol Building in Washington, D.C., though some sources also mention the White House as an early or alternate concept.

What investigators say about the target

Most official and historical reconstructions point to the Capitol as the intended target:

  • Evidence from the 9/11 Commission and later analyses indicates that al‑Qaeda planners discussed the U.S. Capitol (“Capitol Hill”) as the primary objective for the Flight 93 team.
  • Interrogations of key al‑Qaeda figures, including Khalid Sheikh Mohammed and Ramzi bin al‑Shibh, describe a plan in which Flight 93’s pilot‑hijacker, Ziad Jarrah, was assigned to strike the Capitol.
  • The National Park Service notes that the aircraft’s systems were redirected toward Washington, and that the reprogrammed navigation and recovered evidence point specifically to the Capitol Building as the most likely target.

In short, while the White House appeared in some early planning discussions, the U.S. Capitol is regarded by investigators and historians as the most probable intended target of United Flight 93.

Why there is still some uncertainty

Even today, you’ll sometimes see wording like “most likely” or “believed to be”:

  • The hijackers never publicly announced the exact target, and the plane crashed in Pennsylvania after passengers and crew fought back, so there was no final strike to confirm the objective.
  • Some accounts of al‑Qaeda planning note that the White House was discussed as a primary aim with the Capitol as a secondary option, and that if a pilot could not reach his target, he was to crash the aircraft regardless.

Because of this, historians and official sites phrase it carefully, but converge on the Capitol as the intended destination.

Quick fact recap

  • Most likely target: U.S. Capitol Building in Washington, D.C.
  • Alternate idea in planning: White House mentioned in early or backup planning.
  • Why it never hit D.C.: Passengers and crew fought to retake the plane, causing it to crash near Shanksville, Pennsylvania, stopping it from reaching any landmark in Washington.

TL;DR:
United Flight 93 is widely understood to have been headed for the U.S. Capitol , with some early planning references to the White House, but the passengers’ revolt forced the hijackers to crash the plane in rural Pennsylvania before it could reach Washington, D.C.

Information gathered from public forums or data available on the internet and portrayed here.