it never really made sense to me how you could travel the same distance in less time if the airplane isn’t going any faster. how is the time reduced?
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Wind speed.
The aeroplanes generally travel at a certain speed relative to the air they are moving through.
If the wind is moving in the right direction the plane will go at its normal cruising speed relative to the wind, but faster relative to the ground.
In 2020 there was a big Atlantic storm which led to [the fastest sub-sonic transatlantic crossing](https://www.bbc.co.uk/news/uk-england-london-51433720) when a flight from New York to London did the journey in just under 5 hours. The 260mph winds boosted the plane’s ground speed significantly enough for it to break the previous record.
Obviously if the wind is against the aeroplane it will take longer.
Plus there may be delays at either end due to traffic at the airports; with planes having to circle to wait for a slot to land.
traveling faster is possible: jet streams can push the plane faster; planes can have unusually light cargo making engines (relatively) more powerful
One if the factors is the wind along the way. If the wind is a tailwind, it’s pushing you along relative to the ground; if it’s a headwind, you need to travel against it. It’s like walking inside a moving train – you add the speed of the train to your own if you’re moving forwards, and subtract it if you’re moving backwards.
> …if the airplane isn’t going any faster.
Sometimes the plane **is** going faster. Others have mentioned wind speed, but something to consider is that airliners aren’t always going maximum speed at all times. Fuel is a big cost for airlines so an important aspect when flying is to consider doing so as efficiently as possible. Pilots will tend to cruise along at the most efficient speed for the aircraft to save money, but they *can* go faster if circumstances demand it.
An example might be if speeding up would better fit the schedule of the airline such as by allowing a connection to be made, or to fill in for a different aircraft with problems. The extra fuel spent would be made up for by avoiding a delay or cancellation of another flight, so the pilots just throttle up and go a bit faster that normal.
Air Traffic Control can also shorten the routing if there is no other air traffic nearby. For example a flight may be going to Waypoint A and then Waypoint B but ATC can give the direction “proceed direct to B” and knock off miles and time.
Another factor that hasn’t been mentioned: Planes don’t always travel at the same speed, there’s usually room to fly faster or slower. For normal flights, airplanes try and fly at a speed that minimises the total fuel burn, however when a flight is delayed, the airline/pilots might choose to fly at a slightly higher airspeed than typical, at the cost of worse fuel efficiency, to try and make up some of the delay
Planes don’t typically travel at top speed, because it burns more fuel. But they can go faster/use more fuel to try and make up time. Just like if you’re in a car and you could drive 70mph but get worse fuel efficiency than if you drove 60mph, so you choose to drive 60. But if you’re running late, then you might step on the gas and go faster even if you use more gas to get there more quickly.
While the other comments are correct that they can find jet streams, the jets also can just straight up fly faster. Jets don’t cruise with the throttle wide open at max speed. Broadly, there are two kinds of drag that a plane has to deal with: parasitic, and lift-induced. Lift-induced drag goes *down* as the plane goes faster through the air because the wings produce the same amount of lift with a lower angle of attack as speed increases.
Parasitic drag *increases* as the plane goes faster. This is the air getting bunched up in front of the plane without enough time to get out of the way. As the plane goes faster, the air has less and less time to get out of the way, so more gets bunched up and drag increases. [Here is a graph](https://en.wikipedia.org/wiki/File:Drag_curves_for_aircraft_in_flight.svg) of the two kinds of drag as airspeed increases. The most efficient airspeed is at the bottom of the curve that shows total drag.
Being at either end of the curve means that you’ll need to increase the throttle to maintain your speed. Note that at very low speeds you could max out the throttle *without* going faster. To fly at that low speed, the angle of attack has to be very high, close to stalling, and extra power gets wasted as drag. To fly faster, the angle of attack has to be lowered – which, predictably, means the plane will temporarily lose lift and drop. This is a very dangerous configuration for the plane to be in: if airspeed drops for whatever reason, the plane will stall and since the throttle is full open, there is no option other than to lose altitude, which is undesirable for hopefully obvious reasons.
Regardless, the point is that the plane uses the least amount of fuel while traveling at the speed where the curve is the lowest. The pilot *can* fly faster, though, at the cost of burning more fuel. Sometimes, that’s exactly what the pilot does: increase speed and accept that it will cost the airline more by burning more fuel than they need to.
Another option is to request a higher altitude from ATC. The shortest path is always the straightest line so all of the planes flying between certain airports want to be following the same line. Having established corridors also helps with navigation, making it easier for planes to safely navigate to their destination. Very long flights like transoceanic flights want to jump into the same jet streams to take advantage of the boost available. To maintain safe separation between planes, air traffic control assigns each plane its own altitude. Planes typically want to fly higher, because the air is thinner and there’s less drag. Yes, there’s also less oxygen for the engines, so the engines lose efficiency, but the net effect is that higher means less fuel burned. That changes the total drag curve mentioned above by reducing the effect of parasitic drag. If the pilot can get clearance for a higher altitude, they can increase the throttle and fly faster while staying in the most efficient part of the drag curve.
TL;DR: The plane *can* just fly faster, sometimes.
Sometimes you do simply fly faster. Different routes have different cost indexes. Ideally the company wants you to fly slow and save gas, but if you need to make up time you push the throttles up a bit more and burn more fuel. Also routes are designed for deconflict traffic, if it’s not too busy you might get to go direct to the destination and shave a few dozen miles off the route.
Often it has to do with the wind. A tailwind helps the plane, a headwind hinders it. They can also negotiate with ATC to get a more direct route in some cases.
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