I have never seen anyone talk about a way to donate money to help AE develop faster.
Many suggestions talk about adding grate features like timetables and more realism from games like Airlinesim and other paid airline simulator games, but adding these features in a relatively short amount of time can cost a lot of money and AE is free. So how can we get these awesome features while still making AE free, by doing what Wikipedia and countless other sites with premium but free features does by having a donation system.
So i propose adding a way to donate to Airline Empires by adding a donation system to the home page or stating a donation camping. The donated money can go to help speed up development of AE4 and many more updates to come.
An indiegogo campaign and start raising money for AE. http://www.indiegogo.com/