Since winning competitions to provide the US Air Force and Royal Air Force with refuelling tankers for fighter jets, Boeing and EADS (European Aeronautic Defence and Space Company) have struggled to convert the potentially lucrative deals into concrete contracts.

The US Congress last year approved an Air Force request to buy and lease 100 Boeing 767 aircraft to replace its existing fleet of air-to-air refuelling tankers. EADS, meanwhile, won a tough competition against Boeing in January when the UK’s Ministry of Defence selected it to build a tanker fleet.