Is This a Water or Communication Tower?

I have lived in Billings for 50 years and this checkered "thing" by the airport bothers me.  The other day I was driving along the top of the Rims and saw new communication towers in silver next to it.  As I ate my fast food fries, I pondered, what the hell is that checkered thing?  As I kid, I just assumed it was a water tower.  As I got older, I realized it might be a communication tower for the airport.  Why would you have to paint it like "Waldo" if it were a water tower?  I know what it is, I just wanted to see if you had any feedback.