The USAF’s current aerial refuelling capacity is 20% below capacity for major operations, according to a US Transportation Command study.

Air Force Brigadier General Michelle Johnson said the study found that, in two of the three scenarios, the air force did not have sufficient air refuelling support in the fleet, according to AirForceTimes.

“In one case, the military would need 103% of the tankers it has; in another, it would need 120% of its fleet,” she said.

The air force has 415 KC-135 tankers and 59 large KC-10s, while the marine corps has 79 KC-130 tankers.

The shortage mainly results from the fact that 19% of the nation’s aging KC-135 tankers are in depot maintenance.

Johnson said a new aircraft would immediately provide more availability and better mission capability rates, compared with the old KC-135s.

The “Mobility Capabilities and Requirements” study comes a week after EADS said it would compete against Boeing in the air force’s $35bn KC-X tanker competition.