to the chunk of air you’re flying in, it’s no different than if it’s no wind, still moving at ~500kts with in the wind. Relative to the ground, yea, you’re making up time or losing time, depending headwind vs tailwind. With that said, with the jet stream itself, a plane can experience turbulence and windshears as a plane moves within/in/out of different portions of the jetstream. Personally, I don’t like those big tailwinds on flights normally over 8hrs long, getting me to my destination early would cost me money. 😉. We actually now program in a Cost Index (CI) for the flight management system to determine a cost effective speed. A low CI sacrifices speed for fuel savings and a high CI does just the opposite, speeds you at the expense of fuel. In my jet, the Normal CI is 150 and can vary from 0 to 800. So, if we have high tailwinds, the company my flight plan us for a lower CI. Also, sometimes we’ll get a message en route to change CI. For example, flight planned for CI150, winds are forecast for historical norms, but we take off 15 mins early. The message might be to change the CI to 0 which may add 10 min of flight time, still getting us there early, but savings us tons of gas, literally. 😉
[Post edited by B777Fr8Dog at 02/19/2019 3:52PM]