Snowspeeder

When stationed on Hoth, the Rebel Alliance modified T-47 airspeeders to become snowspeeders, fast flying conveyances for patrol and defense of their hidden base. It took some doing to keep the crippling cold from permanently grounding their airforce, but Rebel ingenuity overcame the relentless Hoth elements.
The T-47 airspeeder is a small, wedge-shaped craft with two forward-facing laser cannons. In its rear arc is a harpoon gun fitted with a heavy-duty tow cable. The snowspeeder is a two-man vessel, with a pilot and rear-facing tailgunner.
The main Alliance snowspeeder unit at Echo Base was Rogue Group, led by Luke Skywalker. This unit was tasked with delaying the thundering Imperial invasion force long enough for Rebel command to evacuate Echo Base.
The Imperial taskforce consisted of AT-AT walkers. The snowspeeder laser cannons were ineffective against such heavy armor, and Luke Skywalker turned to a tactic of desperation. He ordered his pilots to employ their harpoons and tow cables to ensnare the walkers' legs. Wedge Antilles and his gunner, Janson, were the first to successfully entangle a walker. With its legs roped, the walker's raw strength brought it crashing down, where the Rebel snowspeeders were able to get a clear shot at its weaker neck column.

Related: Hoth Echo Base AT-AT