The Airboat is a Resistance vessel apparently built from scrap and spare parts. Nimble, fast, and capable of traveling over both water and land, it is ideal for navigating the City 17Canals. It is unarmed at first, but is later retrofitted with a pulse cannon salvaged from a Hunter-Chopper, making it a very deadly threat to Combine forces.
The Airboat is introduced to the player towards the end of the chapter Route Kanal at Station 6, which is destroyed by a Headcrab Shell bombardment as Gordon passes through it. There Gordon is given the boat by Arlene to reach Black Mesa East faster and more safely. He then makes his way through polluted canals and wetlands and is soon spotted by a City Scanner, prompting nearby Civil Protection units to give chase. Freeman manages to evade them, until eventually a Hunter-Chopper joins the chase.
After being pursued for miles, Gordon temporarily loses the chopper in some tunnels, and comes across a hidden Resistance station. There a Vortigaunt mounts a pulse cannon on the boat, providing a powerful offensive capability. Gordon is now able to defend himself more easily against Civil Protecion, APCs and the Xen wildlife swarming the Canals, and destroys the chasing Hunter-Chopper near a dam right before Black Mesa East. When Gordon reaches Eli's facility, he leaves the Airboat behind. It is then presumably captured and/or destroyed by the Combine as they invade the base.
A fast and compact vehicle, the Airboat is well suited to the high speed navigation of the Canals. Though unarmed at first, it can be used to ram any CP unit foolish enough to stand in the way of it. Once the Airboat is armed, however, its lethality increases significantly. The Hunter-Chopper pulse cannon is an extremely powerful weapon, capable of punching through the armor of both APCs and Hunter-Choppers. In addition, ammunition supply is not a problem, as the ammo 'recharges' as it is used. However, burst fire is regularly needed or ammo will run out in around two seconds.
Several puzzles involving Resistance installations are required to be solved to be able to proceed further. Two involve a springboard that must be raised with a counterweight. One has to be filled with any heavy props found around it, the other with floating blue barrels.
The Airboat was originally a Jet Ski but did not playtest well. When the Airboat (then known as the "Mudskipper") replaced it and was first tested, it caused motion sickness. If the player's view was tightly connected to the vehicle, every slight bump was magnified, making some early playtesters nauseated (Adrian Finol, programmer, even threw up after an extended playtest). A careful redesign of the handlebar, pontoon and roll-cage were subsequently made, ending with the current version.
The first Airboat model can be found in the playable Half-Life 2 Beta files. It is longer and its textures are not completed.
The Airboat is almost impossible to knock over. Even executing 180° rolls will almost always result in the vessel not flipping itself. This is most likely to prevent players being stranded with an unusable vehicle, since it would be impossible to turn it over by external means, the Gravity Gun being not acquired at that point of the game. If need be, however, throwing a grenade under it, or targeting it with an MP7 grenade will cause it to right itself.
Two Orange Box Achievements, "Anchor's Aweigh!" and "Heavy Weapons", require acquiring the Airboat and having the pulse cannon mounted on it, respectively. One cut Achievement, named "Catching Air", was to require floating at least five seconds in mid-air with the Airboat.
A pulse cannon similar to the one salvaged by the Resistance and added to the Airboat can be found mounted in a small tower near Gate 5 in the Canals. Freeman uses it to fire at the pursuing Hunter-Chopper.
The Airboat appears to be powered by a straight-six configuration engine. However the engine statistics and output power are unknown. This is observed in-game by the 6 vertical columns located on the engine.
The player is able to activate the Airboat's headlight by turning on their flashlight while piloting the Airboat.