As my name suggests, IAH is a frequent trip for me. The LHR-IAH journey time has always been 10h give or take 10 minutes on each side for seasonal variance (i.e anywhere between 9h50m to 10h10min).

I've just noticed that for the upcoming winter season that the flight times are showing an outrageous 10h50min. I'm not entirely sure how this is accurate and genuinely think they have added an hour onto the flight time by accident.

Today's BA0197 is scheduled at 10h10min this year (was 9h50min last year). Where is this extra 40min-1hour in flight time coming from? I'm noticing that LHR-PHX and LHR-SFO is the same flight time of 10h50min- it being considerably further from LHR than IAH.

More confusingly the return is still scheduled at 9h flat. Whlist it always takes longer to go UK-USA due to winds etc, it does not add nearly two hours to the time to fly USA-LHR

The same PHX-LHR (that is scheduled at 10h50min) takes 9h50min on the return. This is a normal difference of flight time of about 1 hour on the return leg.

Is this a mistake of flight time or is there some convoluted explanation as to why this is the case this season and not previous ones (like LHR ground traffic)?