Space Trucker

We got music in our solar system!
We're space truckin' through the stars!

—Deep Purple, "Space Truckin'"

When space westerns decide to get literal with the genre name, these guys tend to show up.

They are usually depicted as, well, southern-fried semi truckers that happen to fly cargo spaceships instead. Usually easygoing, unflappable, and have a backwoods wisdom developed during the time spent alone on long hauls between solar systems. Occasionally they're smugglers, but usually aren't drug mules. From time to time, between hauls they'll stop at a local tavern and challenge various folks to a little arm-wrestling, drinking contests and then drunken brawls. Tend to talk in a Southern or slight Texan drawl.

Overlaps occasionally with the Boisterous Bruiser, Gentle Giant, Warrior Poet or other ersatz cowboy-style archetypes.

Their ships are most likely Used Future pieces of junk, just barely held together—bonus points if they're blocky, and bear a surprising resemblance to modern Mack trucks or other 18-wheelers.

Depending on the traditions emphasized, a close relation with a tramp ship (cargo ship unattached to a line), a bush plane, or whatever. The commonality will be an independent minded old salt carrying goods with his rustbucket.

A subtrope of Intrepid Merchant

Examples of Space Trucker include:

Anime and Manga

Cowboy Bebop - The episode "Cowboy Bebop/Recap/Session 7 Heavy Metal Queen" focuses on hunting a wanted space trucker named Decker. Another features a group of small time Space Pirates who make a living by robbing other space truckers.
Zone of the Enders: Deloris, i - Main character James Linx runs a cargo ship around the Sol system. He copes with the boredom of weeks long journies with beer and reading.

Comic Books

2000 AD's Ace Trucking Co. series.
While less of a trucker and more of a taxi driver, DC Comics has Space Cabbie, who has been shown transporting and imparting wisdom to everyone from Adam Strange to Ultra, the Multi-Alien.
The mostly-forgotten (for good reason) Marvel hero Razorback had the mutant power to drive any vehicle seemingly by instinct. He happily moves up from semis to FTL spacecraft.
The 2010 Infinity Gauntlet mini-series includes the character U.S. Ace, whose Space 18-Wheeler (it looks like a semi-truck with rocket boosters) is the fastest ship in the galaxy, and therefore the chosen ship for The Avengers to use to get to the center of the universe.

Film

Spaceballs (a parody of Star Wars) naturally has Lone Star (a parody of Han Solo) driving a Winnebago through space.
Space Truckers. You don't say. Right down to the spaceship looking like a Mack truck.
The crew in Alien.

Literature

John DeChancie's Skyway trilogy epitomizes this trope, as in the setting the only widely known form of faster-than-light travel involves driving ground vehicles along the highway/wormhole network Precursors have built which seems to connect every place in the universe worth visiting. Most races don't even bother building sublight spaceships (though they do get used), and if anybody has actual FTL space drives they're keeping it very quiet, so trade equals truckers. And human truckers tend to be... well, truckers.

Live Action TV

The Eureka Maru in Andromeda.
The Star Trek: The Next Generation episode "The Outrageous Okona" had the Loveable Rogue variation in Okona.
The Lexx episode "Love Grows".
Firefly: The crew of Serenity have this as a major part of their job. Of course, they also do burglaries and mercenary work.

Music

"Asteroid Named Rest Stop", a Filk Song by Julia Ecklar and Leslie Fish. The lyrics can be found here.
Obviously, "Space Truckin'" by Deep Purple.

Tabletop Games

The aptly named board game Galaxy Trucker.
Free Traders in Traveller, though there the preferred analogy is of "tramp" (non-scheduled) ocean freighters than of truckers. In some ways Traveller is a subversion. Even a free trader costs enough for any one who owns it to be accounted as rich even if not as rich as an interstellar grandee.

Webcomics

Nip and Tuck's Show Within a Show (movie within a comic?) "Rebel Cry" was based around a space trucker with a bone to pick with the Evil Empire.

Web Original

Not uncommon in Fenspace, where the space trucks might well be actual trucks converted to spacecraft with handwavium. A good example would be the original Vitamin Man and his imitators/successors, who sold nutritional supplements to early Fen settlements out of space-capable panel trucks and vans.

Western Animation

The Planet Jackers from Invader Zim are quite reminiscent of long haul truckers.
One episode of Futurama has a space trucker convoy. Their role in the story was basically just to throw cat calls at Leela.