anchor.diff:      alliance: function(){
         return this.data.alliance;
       },
  +    airports: function(){
  +      return [this.data.origin, this.data.destination];
  +    },
       origin: function(){
         return this.data.origin;
       },
  
positive.code:     alliances: function(){
        return _.uniq(this.get_flights_values("alliance", true));
      },
  
      airline_duration: function(){
        return _(this.list()).chain().
        reduce(function(hash, flight){
  
negative.code:     memoize: [],
      context: function(){
        var data = {};
        var self = this;
        _.each(["airlines", "airports"], function(name){
          var list = self.direct_flights[name]();
          if(self.return_flights){
            list = list.concat(self.return_flights[name]());
          }
          var collected_data = {};
          _.each(list, function(id){
            collected_data[id] = NANO.api[name].get(id);
          });
          data[name] = collected_data;
        });
        return data;
      },
  