Check Six Enterprises  
   Original designs by pilot/artist Russ Hopf. Images range from homebuilts to jets, through many eras of flight.
   http://www.cygrfx.com/check6/

Leatherneck Air Corp  
   Aviation related T-Shirts. Also has airplane pictures.
   http://www.leatherneckaircorp.com

Airplane T-Shirts  
   Dozens of multicolor designs covering general aviation, warbirds, homebuilts, ultralights, and helicopters.
   http://www.airplanetshirts.com/

TriStar  
   Aviation art from your favorite American airlines, past and present.
   http://www.skyshirts.com/

Aviation Gifts  
   A collection of simple slogan shirts aimed at aviators and their families.
   http://www.aviation-giftshop.com/

Epic Skyriding Company  
   Designs for paraglider pilots.
   http://www.epicsessions.com/

Sophos Silk Screening  
   A collection of American military designs.
   http://sophoswear.com/