Just adding to this thread with a permutation. I'm flying out of T3 tomorrow on a 9:35am AA flight to the US -- I won't have checked bags, but am only OW Ruby so no fast track checkin. I'm planning to take the Elizabeth line to the airport for the first time - is taking the train scheduled to arrive at LHR 2 hours before my flight safe? Not sure if there's a long walk from the underground station to security, or if I'm cutting it close without fast track security. Thanks for the advice.