That link has this question: “Why do the departure and arrival times on a scheduled airline differ from the information on the airline’s web site?”
I am not talking about the airlines website. For example, on the crew website for American Eagle, we have out, off, on, in times (from our acars). Out of the gate, off the ground, on the ground, in the gate. For a flight, I may show the OFF time as 9:01am while flight aware shows it took off at 9:03am and landed at 10:41am, even though the employ website shows it landed at 10:38am. Our times are from our ACARS. Just curious as to why the TO and Landing times are different from our acars to your times on FA.