The late researcher Gerard Holmgren identified this fact and made it public on November 13, 2003.
By 2004, the BTS records showed something completely different about these flights. The new explanation said the following:
" On September 11, 2001, American Airlines Flight #11 and #77 and United Airlines #93 and #175 were hijacked by terrorists. Therefore, these flights are not included in the on-time summary statistics."
As a public employee, I can safely assert that doctoring an official record is a serious matter. Public employees (and probably private ones, too) may be fired for engaging in this conduct. It seems someone up high did not want the public to see the original records.
With the official theory telling us that both flights were hijacked and smashed into buildings, it should be obvious that this is one more reason to call the official theory a lie.