New York

SOMETIME this summer, a United Airlines flight will take off from Los Angeles International Airport bound for San Francisco using fuel generated from farm waste and oils derived from animal fats.

For passengers, little will be different - the engines will still roar, the seats in economy will still be cramped - but for the airlines and the biofuels industry, the flight will represent a long-awaited milestone: The first time a domestic airline operates regular passenger flights using an alternative jet fuel.