[reed13k]

I understand why the Naval version for carrier landings and takeoffs needs to be different.

Taking off that mod for additional fuel/loadouts makes sense, but I’ve never understood why the rest couldn’t be the same.

[Eric Pode of Croydon]

Carrier landings put stresses on landing gear and airframe that runways never do.

There have been three plans that have worked well in both settings which I can think of: the F-4, the A-4, and the A-7.

All three were designed and bought for Navy use first, before any land-based air force decided to try them.

[PAR35]

but I’ve never understood why the rest couldn’t be the same.

Because the Air Force version can't land on the mini-carriers used by the Marines. (Neither can the Navy version, for that matter).

Better question is why the Navy couldn't use the Marine version, and build cheaper, smaller, carriers. The USS Ford cost over $16 billion, they've been working on it over 6 years, and it is supposed to be ready in a couple of months, and is an easy target for the Russians or Chinese - even, perhaps, the Australians.

[TalonDJ]

“but I’ve never understood why the rest couldn’t be the same.”

Vertical Take-off.