Our intuitive experience with wind on the ground is wrong. Next time it’s windy outside imagine the entire volume of air stretching out for miles and miles moving across with the wind speed, we’re just standing at the bottom of this vast air ocean. It will blow your mind and you’ll think about wind differently from then on. So with that in mind, once the airplane is in the air, it doesn’t “know” if there’s a headwind or a tailwind at all, unless you have a way to reference the ground somehow (for example, with a GPS) - just like a boat doesn’t “know” it’s carried by a current downstream. If you are still on the ground, it is very possible that the tailwind is strong enough for you to not be able to takeoff in the available runway - but then you would go in the opposite direction or more likely sit the storm out :)
> So with that in mind, once the airplane is in the air, it doesn’t “know” if there’s a headwind or a tailwind at all
This stops being true for quick changes - because there's still the inertia of the aircraft. So if the wind speed changes quickly, the aircraft can't immediately move along with it.
This is why gusts are so dangerous to landing aircraft. A strong gust from behind can cost you all your lift, and a strong gust from the front can temporarily stall your wing.
I’ve noticed this effect while diving. When you’re in a current, you’re basically the same density so you’re moving with the water. In mid-water with poor visibility, this is really freaky, because you have no way of telling in what direction you’re moving, and how fast. If you “forget” your orientation, you can’t really recover it. Thankfully, you always have highly accurate depth gauge, but as for lateral movement, it’s an eerie feeling. You could just pop up anywhere.
Yeah, I wish meteorologists explained this concept better to the general public, since they're basically poised for it. One day I was just wondering where wind _started_ from, and started digging deep into the topic, but essentially we're all just standing on the bottom of a roiling ocean floor that is very sensitive to heat changes from the sun.
