Originally Posted by
Skatering
You also have to compare like-for-like.
LHR flight times include the long queue to get onto the actual runway and the almost guaranteed need to hold on the return. At LGW, it's much quicker to get onto the runway and holds are less likely.
That's actually the opposite of what the schedule is. The TS flight from LGW is the one with the longer schedule time. More likely the difference is due to aircraft type, as the AC and BA flights from LHR operate with a Boeing 787-8 and the TS flights from LGW use an Airbus 330-200. The 787 has a standard cruise speed of mach .85 (487 knots) while the A330 has a slower standard cruise speed of mach .82 (470 knots). This speed difference would account for at least some of the difference in flight times and climb and descent speed could account for additional differences. It's also possible that TS flies even a little slower for greater fuel efficiency.