[spydez]

Off the top of my head: that plane had a jet engine, so they could just route their air lines near the engine for heat, or siphon air from the jet directly. Then just constantly 'leak' some warm air from all the holes on the wing surface when in icy conditions.

Or just electrically heat the metal around the holes, like is currently done for the pitot tube (speed indicator).

[kwantam]

Large airplanes usually have electrically heated leading edge surfaces in addition to pitot tube and stall indicator heat. As you point out, something like that would work well in this application. There is something of a drawback, though.

On mid-size planes rated for icing flight, "ice boots" are generally used. Boots are a rubber surface over the leading edge of the wing that can be inflated on command. Once ice buildup is sufficient to warrant their use, the pilot engages the system, which compresses air and then inflates the boots violently, breaking the ice off the leading edge.

The reason this is more popular for smaller airplanes is because electrically heated wings take much more power than you can reasonably expect to generate on something smaller than business jet sized (e.g., Cessna Citation), especially on approach when engine output is reduced (and when icing can become the most problematic). Even medium-large twin turboprops like the Beech KingAir 350 rely on boots.

An alternative technology for smaller airplanes that's pretty unpopular is the weeping wing, wherein a deicing agent is pumped out through small pores in the leading edge. It's unpopular because you either have to carry a lot of weight in deicing solution or risk running out. My father flew a Beech Bonanza A36 that he had retrofitted with the weeping wings, and he's remarked on many occasions what a pain in the ass they were.