Now, however, many of the big airlines have reduced their costs through two-tier wage structures and by using more efficient aircraft.

But United said the schedule reductions would lead to savings of $1.2 billion because the airline would rely on more efficient aircraft.

Airbus executives argue that the steady growth in air travel requires bigger and more efficient aircraft.

IL-76 "Candid", a heavy ramp freighter, is one of the most efficient and demanded aircraft.

Pharmaceutical companies use them to produce new drugs, for example, and they are essential for designing the most efficient aircraft.

More competition encourages the use of modern, efficient aircraft.

These are extremely efficient aircraft in terms of fuel, training, maintenance and crew costs per passenger.

The organization promotes experimental aviation activities which promote the development of highly efficient aircraft.

Rival carriers have placed major orders for new, more efficient aircraft.

It should provide incentives to renew fleets and create more efficient, more modern aircraft.