Convertion and upgrade options

[joaoc]

Hi,

I'm requesting the following, upgrades are available for aircraft such as winglets for example for the a320.
The thing is, in reality after they became an upgrade the new planes are built and leave the factory with the winglets and not with the wingtips, i believe it as now become the standard.
So for instance, in the game, older planes are the ones that could have the option for upgrade, the newer planes, after that upgrade appears, have them installed as new.
Hope you will adress this 

Thanks!