Why can’t aircraft carriers just have longer runways?

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I’ve seen the Pearl Harbor movie where they make a big deal of taking weight off the planes because the ship’s runway is just too short. Why can’t they just be longer? Or was just that because they lacked the time during ww2?

It seems like the problem still exists today and i just don’t get how a massive ship would be affected by a longer runway. Maybe make it telescoping like a firetruck’s ladder so it can be retracted during bad weather.

What’s the limiting factor here?

In: Engineering
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Pitch. The longer the runway the more the beginning and end of the runway move vertically up and down

Aircraft carriers have hooks that help slow the planes down when they land. A aircraft carrier big enough to have a full runway for a plane to land without extra help would have to be absolutely massive.

It would be more reasonable to call such a craft an island rather than a ship.

The aircraft carrier would have to be *a lot* longer to support most planes loaded with max payload, which is why we use catapult launches today.

A Nimitz class aircraft carrier is just(?) 332 meters long, this seems like a good distance until you learn that the **minimum** takeoff distance for a fighter like the F18 (not even the super variant) is around 500 meters and that’s the minimum distance when not heavily loaded.

You’d have to make your aircraft carrier at least 50% longer to support unassisted takeoffs of heavier aircraft. This makes it significantly more expensive to build and operate, often slower and less maneuverable to boot.

Modern aircraft carriers all have either catapults to assist takeoff or a ski jump at the end up the runway to loft the plane up and give it a bit more time to pick up speed before it impacts the water.

Carriers are already absolutely massive, and expensive.

Anything mechanical (like a telescoping mechanism) is more expensive (to build AND to maintain) and subject to breaking, especially at sea.

WW2 planes also had a lower power to weight ratio than modern jets just because of technological and metallurgical advancements.

Fighter planes need about 3000 ft. of runway. If a carrier wanted to put in full runways, they would both a take off and landing runway—so you can launch and recover at the same time. They aren’t exactly placed to end to end (there is a bit of overlap) so the combined runways would be about 5000 ft. long, or about 1500 metres. The longest ship ever built was 458 metres. This means a full runaway carrier would need to be three times larger than longest ship ever built.

That is a huge ship. A ship that largest would never be able to fit into any harbour or dry-dock. You wouldn’t even be able to build a ship that size with any current location. Also, a ship that size would require a lot more power to move properly. Instead of using more power to move the ship, they use a minimal amount of power to launch and land planes from a shorter runway.

The runway isn’t 15m short or something. The minimum recommended runway lengths for ground based fighters are above 1km. The Nimitz is one third of that length.

I see alot of good answers here but most people neglected two of the most important characteristics a naval ship needs. Speed and maneuverability.

If an enemy ship or submarine launches surface to surface missiles or anti ship torpedos, that carrier must be able to manuever to try to avoid that inbound weapon fired at it.

There are reasons that aircraft carriers are pretty safe. 1 i will mention is that the carriers are very fast. They can actually outrun some older model torpedoes. And they are also capable of conducting evasive maneuvering.

If you made the carrier significantly longer – you would give up some combination of speed and maneuverability which would make it more vulnerable to enemy attack.

In the Pearl Harbor movie they were using bomber that were not designed to launch from a carrier. This is why they had to make them lighter, since it was a special mission, a symbolic move to bomb Japan, even when the USA didn’t have any airfield close enough to Japan to do it.

When you design a carrier and planes you need to reach a balance. A carrier can’t be long enough to launch any planes. Even most airfield are limited, the biggest one are longer than 3km long. Most airfield on the ground are not that long and can’t have some of the biggest planes land or take-off at max weight there.

That would be ridiculous to make a 3+km long aircraft carrier, so you need to make a decision, what is the optimal lenght, a good compromise between which aircraft you can launch and how costly your aircraft carrier will be. We don’t have infinite ressources, and so you need decide, do you want one very big aircraft carrier, or several a bit shorter. The second option give you more flexibility and it’s usually a better option. You also have to decide if you want to use the total lenght of your carrier for landing and take-off. If you choose that option, you can’t do both at the same time and this against limit your flexibility. This lack of flexibility is one of the reason that cost the Japanese the battle of midway, since they couldn’t recover the planes that attacked Midway and launch the planes to attack the incoming US carrier at the same time. The modern US carrier used only half of the lenght (roughly) for launching their planes with catapult for that reason. Everything in life is about compromise, if you want your aircraft carrier to be able to launch any planes, you gonna need to sacrifice so much in other aspect that it will most likely be a very bad ship and a big waste of money.