F15 jets being refueled by a Boeing 707, while in flight. Aerial refueling allows medium-range fighter aircraft to operate at greater range from their bases. This technique, which involves the trailing fuel boom being steered from the tanker to dock with the approaching aircraft, is used extensively throughout the world. A very large proportion of the fuel capacity of an aircraft is used in taking off, so this system is relatively fuel-efficient. These aircraft are part of the Israeli Air force.