Insight, you probably don't need High Performance Aircraft in Traveller, unless you're from a low-tech planet. Piloting pretty much any suborbital craft is covered by the Pilot (Gravitic) skill. Low tech planets...which are actually pretty common throughout the Imperium...might still use wheeled vehicles, or winged (fixed or rotary) aircraft, but they're not the default assumption.
Traveller spaceships typically only mount three weapons, unless they're military ships.
Lasers are used for point defense and for deterrent offense. They can threaten lightly armored civilian craft, but aren't going to be much of a threat against thicker-hulled vessels unless you have a large ship with powerful weapons.
Missiles are the primary offense of civilian starships. A missile hit or two can cripple a small civilian ship, and make even heavier ships think twice about engaging. Missiles don't have a Gunner skill, I don't think. The missiles are guided, and have their own "skill rating" that is used in place of a gunner's.
Sandcasters are a form of defense that's effective against lasers. They shoot canisters of what is essentially ground up glass that burst at a programmed distance from the ship. A good gunner can use this weapon to saturate space between his ship and an enemy ship with particles that diffract and diffuse incoming laser beams, reducing their ability to do damage. Sandcasters don't have much offensive value. In theory you could play games with relative motion and create clouds of relativistic sand...but in practice it's a lot easier just to shoot something with a weapon that's designed for it.
If you're military, you might get some of these other weapons. And note that they're not -restricted- to military vessels. They're just really expensive and high tech, and thus rarely seen on civilian ships.
There's plasma guns, which fire high velocity jets of hot plasma. They tend to attenuate over range, making them less useful. Their high-tech cousin is the fusion gun, which ejects a stream of plasma that's so hot that it's actually undergoing a fusion reaction as it fires. They're basically just super-plasma guns, that do tons more damage.
Large ships can mount particle beams in large turrets called "bays," and on fixed spinal mounts. A spinal mount is basically a gigantic gun emplacement that's built into the ship's structure along it's center of thrust. Sort of like the Wave Motion Gun from the Space Battleship Yamato cartoons (Star Blazers in the states). Particle beams are enthusiastically nasty, but are capital ship guns, normally used on other capital ships.
And of course, there's the granddaddy gun of them all. The meson gun. Meson guns generate a cloud of subatomic particles that only interact very weakly with normal matter, and accelerates them at relativistic velocities towards an enemy ship. The mesons decay back into normal matter and energy after a very short period of subjective time, but that time can be manipulated by controlling the speed that they're launched at. The closer to the speed of light, the longer their lifespan appears to be from an outside frame of reference. A complex calculation can therefore determine precisely what velocity they need to travel at in order to time their decay so that it takes place while they're in the process of passing through the enemy ship. The meson decay is violent, releasing a great deal of energy in the form of heat and hard radiation; something not far from detonating a tactical nuclear device. Meson guns are always spinal mounts, though they don't need firing apartures or any obvious sign of their presence.
