“Going by their outward appearance, they are completed.” (Wendelin)
“The question is whether the large magic gem inside is safe or not.” (Burkhart)
Being a legacy of the past, it is depending on the large magic gem being safe in the engine room whether it is possible for the magic airships to re-enter servitude or not.
Since a number of years have passed, there are many situations where they have already broken down due to magic gem of poor quality.
With the current technology it is only possible to have the magic airships fly, but producing the necessary magic gems for that is difficult.
The technique of creating a large magic gem by using several small magic gems as ingredients, as it existed in the past, has been lost.