http://flightaware.com/about/merchandise/
FlightAware isn’t profiting off any of these products, so please do not feel obligated to buy anything simply to support the most popular flight tracking service on the internet.
Who does profit, if you don’t mind me asking…
Either way I’m gonna buy a “Ringer T”.
Just curious, I think the profit should go towards the site. This is a remarkable free resource to most of us and you should take compensation wherever you can get it!
We assume Spreadshirt (the vendor who handles all the merchandise) makes a profit, or just really really likes printing and shipping.
Shirts look nice, but sure wish they had hats !
Baseball caps would be nice. Mark!!! Make it happen, lol. 
Spreadshirt is a company my daughters have used, and they seem satisfactory. I gather that their business model includes a lot of single shirt orders. I don’t have any judgment about their competitiveness.
Does FA provide them with an official logo and license them to apply it to shirts under certain guidelines? Is it a non-exclusive deal? I’m asking because I googled “logo baseball cap” and came up with a few companies right away. I don’t have any way to judge those companies, either. So to be a bit safer you could license more than one of those companies to make FA logo caps, and let the market tell you which company is better.
We’ve had a good experience with Spreadshirt and we’ll add baseball caps to the page there. We’d rather not provide links to a dozen companies we’ve never worked with and say “good luck.”
I just added two baseball caps to the shop. I’m unfamiliar with Spreadshirt’s baseball caps ] so if anyone buys one please report back and let us know how it looks and fits.