Have you ever wondered how your airport paid for that brand new, multi-million dollar runway?

In the US, airports are usually publicly owned utilities, meaning that they receive funding from both public and private sources. But the federal government doesn't directly operate many airports; management comes from airport authority groups, which branch off from local and state governments.

We just made a visit to Denver's Centennial Airport (KAPA) to find out more, and here's what we found:

1) Airports included under the National Plan of Integrated Airport Systems in the USA are eligible to receive government grants from the Airport Improvement Program (AIP).

2) Airports charge flowage fees (a dollar amount per gallon of fuel sold by an FBO). And at many airports, it doesn't matter if the company selling fuel loses money - the flowage fee is required.

3) At many commercial airports, airlines pay usage fees for terminals, gates, services, and passenger counts.

4) Airports often make large amounts of money from non-aviation land leases, rental car charges, and retail space fees.

5) For instance, at the West Palm Beach International Airport in Florida, non-aviation sources accounted for more than 60 percent of the airport's operating revenues last year.

6) Landing fees are common, which may or may not depend on the size of your aircraft.

7) Some airports require FBOs to pay a minimum capital contribution toward airport infrastructure.

8) At Denver International Airport, you'll need to build at least $10 million of infrastructure to open a new FBO. And once your lease is up, the airport owns your property.

9) Excluding privately owned airports, land users pay for their lease but own none of the actual property. FBOs are often tasked with maintaining their multi-million dollar ramps and facilities. Basically, when it comes to FBO management - you built it, you pay for it, and the airport owns it.