This paper model is a Airboat, based on the Half-Life game series. 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 17 Canals. 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 the Metrocops, the 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.