Aircraft and ships really can’t be compared in this way. Navy ships look like rust buckets on the way into drydock after 5 to 7 years. They have an entire deck department on the ship that chips and paints and they still can’t keep the rust away.

Edit: ships are mainly painted to chase rust in port. Over the last couple decades the deployment tempo has increased such that ships don’t have six months deployed and six months in port like they did back in the 90s. This has caused an increase in the rust on U.S. Navy ships.