York to Heathrow Airport
 

I'm leaving York at noon on a Sunday and need to get to Heathrow airport for a 5:15pm flight. It looks the train to King's Cross is about 2 hrs and then another 1 hour to on the underground to get to the airport. Did I cut it too tight on time, is 3hr prior check in time really necessary from the UK to the states?

<i>Did I cut it too tight on time</i>

Yes - the EARLIEST you'll reach Heathrow is 3:15pm, check-in / bag drop will probably close 1 hour before scheduled departure time so that leaves 1 hour for any little problems - train is late, Tube gets stuck...

When is this? According to the trainline and the current schedules, there is no noon train on Sundays. Closest is the 12:31 arriving Kings Cross @ 14.52. Leaving KingsX on the piccadilly line at 15:19 arriving T-3 @ 16:25. (Just using T-3 as an example)

Not only will you not have 3 hours, you'll have less than 1 hour.

(there are earlier tube trains, but they involve multiple tube/walking/train transfers)

If you catch the 11:39 from York, you'll arrive at KingsX at 13:54. Leave KX at 14:19 arriving at T-3 15:25. So even using the earlier train you'll have less than 2 hours.

Not nearly enough time. Yes - you need to be there 3 hours in advance. Planes are full, check-in lines re long and security is often a mess (there always seem to be bunch of people who don;t have a clue abut the process and gum up the works). I got stuck behind a guy trying to take a KNIFE on the plane (hanging inside his pants by a loop from his belt. He was setting off the metal detector and they had him take the belt off since it had a large buckle - and this knife attached to the belt came out with it. That held the whole line up about 20 minutes - while they called in a bunch of extra security people, collected him, his luggage and his traveling companion and hustled them off. (And yes - he was either American or Canadian based on his lack of accent.)

<i>According to the trainline and the current schedules, there is no noon train on Sundays</i>

There's an 11:56 train from the end of July.

I would never want to be that far from the airport the morning of my flight...weekend engineering works could impact train travel and tube travel. Trains/tube could be delayed or cancelled. I would either take a much earlier train or be in London the night before because I don't like that kind of stress.

alanRow. Good to know. That's why I asked when the trip is. But for some reason, for say July 29 tfl journey planner shows no piccadilly line trains. Only H&C to Paddington and then the (EXPENSIVE) HEX.

Is that maybe because of the Olympics prep or engineering works on the Piccadilly line??

Out of curiosity, I plugged in a journey from farther down the Piccadilly line (south Kens) and there are some through trains.

In any case -- doesn't really help the OP . . .

Thank you all for the very helpful comments. The bottom line appears to be that I need to change my plans and leave York much earlier. I believe there is an 8am train.