The Royal Air Force is expected to receive its first E-7 Airborne Early Warning and Control aircraft in 2023.
Responding to a written parliamentary question on Monday, Minister for Defence Procurement Jeremy Quin said the fifth and final E-7 is set to arrive in 2026.
The RAF previously said the aircraft, known as the 'Wedgetail', was expected to begin service in the early 2020s.
"I am withholding the detailed delivery schedule as this would, or would be likely to, prejudice the capability, effectiveness or security of our Armed Forces," Mr Quin added.
Last year, then-Defence Secretary Gavin Williamson signed a $1.98bn (£1.5bn) deal to purchase five E-7 aircraft.
The E-7 is set to replace Sentry aircraft as the UK's Airborne Early Warning and Control capability.
The aircraft is based on a civilian Boeing 737 NG airliner.
It was reported last year that two of the jets' airframes would be second-hand.
Mr Quin reiterated that they are "low-hours, previously owned aircraft".
"Boeing will undertake a thorough overhaul of these airframes to ensure a standard form, fit and function across the whole fleet," he said.
"This will enable all aircraft to be operated and maintained by the RAF in the same manner."
The aircraft is already being used by the Australian Department for Defence.
It can fly for long periods of time and manage the battlespace from the sky.
It is hoped the new aircraft will be able to track multiple airborne and maritime targets at the same time.
Any information gathered by the E-7 Wedgetail will be used to provide situational awareness and direct other assets such as fighter jets and warships.
Cover image: A Royal Australian Air Force E-7A at Nellis Air Force Base in Nevada, USA (Picture: US Department of Defense).