Quick questions B737's and Airbus orders say the production line is closed does that mean we can no longer order new aircraft and will only be allowed to purchase used ones?
Well .. the particular game world you are in is about to end in about 2 hours anyway, so that's probably why nobody has made any large orders recently.
But yes, if the line closes, then those models aren't available anymore from the factory. https://www.airwaysim.com/game/Manual/Aircraft/New/#ProdSlots