Instructions
Build additional administration buildings on your airport as it grows throughout the game. As your airport grows in size you will need additional administration buildings to handle the heavy workload. With administration buildings comes workers. Workers fix problems with your airport and keep everything maintained, which keeps your satisfaction rating high.
Pay attention to what your customers are complaining about. Periodically you will receive feedback from the customers who use your airport throughout the game. If a number of customers have the same complaint, do everything you can to address that complaint. For example, if flights aren't taking off on time, build additional runways. This will get your customer satisfaction rating increased, which will pave the way for contracts.
Keep your airport clean and immediately repair any disasters like storms or crashes. If something breaks down on your airport, click on the area the disaster took place in and fix it immediately. Doing so will keep not only your customers but your existing contracts as happy as possible. Both of these things lead to additional contracts, which leads to an increased revenue stream.