Earlier in the month, UA tested a new fuel savings maneuver on a Chicago-Frankfurt flight in which pilots were given greater leeway in setting their flight path. This allowed them to better utilize favorable winds.
While 900 gallons of fuel were projected to be saved, it turned out 1,400 gallons were shaved off.
The test flight provided a sneak peak of the future of ATC, in which updated technology will allow all flights to exert greater flexibility in their flight paths, thereby conserving fuel and cash.
For more technical details, see this article.