llalyr,

While not a problem of cobras, Guam has a continuing problem with brown tree snakes. Departing ships and aircraft are routinely inspected for the brown tree snake. Not sure if they have made it into the cabin, but they like the aircraft's wheel wells. The shipyards, airports, and power stations (they get on the power lines and cause power outages) employ countermeasures (dogs, traps, etc..) to assist in capture of the snakes. The brown tree snake is not native of Guam, it was probably transported to Guam on a cargo ship after WWII. A Google search will produce lots of information on the pest.