I’ll be taking a 9:50 flight from Heathrow back to the states. What time would you all suggest getting to airport? I’ve never flown out of Heathrow. Also, I’m staying near Paddigton and there is a 5:10 express train. Would that get me to the airport pretty quickly? TIA
Arrive by 6:50am. 3 hours is plenty.
You won't need the 5:10 HEX train unless you prefer getting to LHR at 5:25. It's 15 minutes to Terminal 3 for example. Allow about a 10-20 minute walk to departures depending on your terminal so you arrive at departures by 6:50.
It says it takes 15 minutes
https://www.heathrowexpress.com/
You should be there no later then 7am. Yes, the Heathrow Express would get you there in 15 minutes to terminal 3 and 21 minutes to terminal 5.
If you are at the airport around 7 am, you will be fine. I would get a train somewhere between 6:15 am and 6:30 am.