Airliner Class Bug?

[autumnnoyu]

Hello,

Thanks for creating this wonderful game!

I've encountered a problem, in that when I have an airliner (leased) that comes with more than 1 class, there is an option to "add airliner class", but the drop down list is empty.
On the other hand, when I have an airliner that comes with only 1 class, there isn't even an option to "add airliner class". 
Furthermore, if I delete a premium class from an airliner that has more than 1 class, the option to "add airline class" also disappears.
Is this a bug?

My start year is 1946, if that matters.

Thanks!

[nnick]

The bug that you see here is that the airliners shouldn't have two classes in the first place. The first class should only become available in 1960. And I believe that in the xml files the early airliners are configured as one class only airliners.

[autumnnoyu]

The bug that you see here is that the airliners shouldn't have two classes in the first place. The first class should only become available in 1960. And I believe that in the xml files the early airliners are configured as one class only airliners.

Thanks!