I think he is very generous to refer to the 3 the UK has on order as a “fleet”….
https://www.defensenews.com/air/2023...o-get-the-e-7/
‘The ability to stare’: Why the US Air Force is eager to get the E-7
…..The U.S. version of the E-7 will be similar to the three Boeing is now building for the U.K., particularly in terms of the air frame, sensor and mission equipment, though the U.S. Air Force made unique requests Boeing declined to specify.
Boeing wants the E-7 fleet to be largely interoperable so it’s easier and cheaper to upgrade different nations’ fleets…..
But Boeing officials reiterated the Air Force’s statements that not much can be done to rapidly accelerate the process of acquiring new E-7s. While the U.K. purchased used planes to convert into its E-7s, Meranda said there’s not many more used airframes available to adapt into additional E-7s…