Surface Pods are small landing vessels carried by the Protector. It appearently has an autopilot system, and is possibly capable of manual control as well. The vessel flew using what is called a "Hyperpulse thruster system" that can fit under the pilots chair.
The Thermians replicated these small vessels, and used them in the same capacity as the fictional version.
Behind the Scenes
The surface pod did not appear in the first few episodes of Galaxy Quest because the cash-strapped studio simply couldn't afford to build the little ship for filming. That changed during Episode 13 when the Galactic: Ice Cream company offered to build the pod in exchange for the rights to use the design in a fleet of ice cream trucks. Not only did the show get a beautiful surface pod, but the cast and the crew got an unliminted supply of Galactic Ice Cream.
The full-sized surface pod prop was originally built as a large booster section, and a small cockpit module. Just before the first use the prop was trucked to the Vaquez Rocks, the filming location for Episode 13, a sudden gust of wind tore the entire booster booster from the flatbed, shattering it onto the roadside.
Only the cockpit remained, with no time or money to rebuild the wrecked section before filming the next day. Direct April Winter decided on the spot that the surface pod didnt need a booster. Instead declared the pod was equipped with a "Hyperpulse thruster system" that happened to be small enough to fit under the pilots chair.