Fuel fraction is a key parameter in determining an aircraft's range, the distance it can fly without refueling.
The Russian supersonic interceptor, the Mikoyan MiG-31 "Foxhound", has a fuel fraction of over 45 percent.
[5] The Panavia Tornado had a relatively low internal fuel fraction of 26 percent, and frequently carried drop tanks.
[6] Airliners have a fuel fraction of less than half their takeoff weight, between 26% for medium-haul to 45% for long-haul.
The Rutan Voyager took off on its 1986 around-the-world flight at 72 percent, the highest figure ever at the time.