I was on my way back from Singapore via Hong Kong and DFW. On the way out I took AA 137 from DFW to Singapore, which is scheduled for 16 hours and 50 minutes. The reciprocal AA 138 is scheduled for 14 hours and 20 minutes, or 2 and 1/2 hours less. Why? Because it is flying with the jetstream versus against it going west.
I witnessed how significant the jetstream can be on my way back from Hing King to DFW. I looked up at the monitor and saw we had a tailwind of 174 mph!
As a result, our groundspeed was an astounding 731 mph!
I don't recall ever seeing a groundspeed over 700 mph.
As a result of the big tail wind, we got in an hour ahead of our scheduled arrival, and I was able to catch an earlier flight home. Hooray for the jetstream!
Also, hooray for upgrades. I was fortunate enough to get upgraded on both trans-Pacific flights. This particular airplane is a 777-300ER, and is quire nice. Here is a review of business class on this plane: