Global travel is good; reducing air pollution (including GHG emissions) is good. Unfortunately, as we've noted in the past, air travel is a significant contributor to atmospheric pollution. The more you fly, the bigger your ecological footprint. Increased use of biofuels might help in the short-term, but solving this problem is going to require some serious effort.
That's what the "Efficient and Environmentally Friendly Aero-Engine" (EEFA) program is about. Coordinated by the European Union, EEFA includes 53 partner groups, including the entire European airplane industry, various national defense and technology agencies and numerous universities. Begun in 2000, the program seeks to (PDF):
Reduce fuel consumption by 12% to 20% Reduce NOx emissions by 60% 80% Reduce cost of ownership by 20% to 30% Improve reliability by 60% Reduce time to market by 50% Reduce life cycle cost by 30%
Ambitious, to be sure, but obviously of great value. EEFA plans to start testing new engine designs this year.
On the biodieselnow.com forum, someone launched the idea for a marketing stunt, just yesterday: flying around the world on pure biodiesel.
Check it out here: http://forums.biodieselnow.com/topic.asp?TOPIC_ID=5074