Boeing P-8A Poseidon (737-800EFV) MMA (Multi-mission Maritime Aircraft)

[Apophenia]

I must've been thinking of the older 737 models including the USAF's C-43 as they're smaller than the C-135 line, it just drives home how big the 737 airframe has grown as it has evolved over the decades since its' first flight in 1967.

It's the wings where the big differences show up between the 'C-135 and 737s/P-8A ...

RC-135 - Wing area 226 m2; span 39.88 m;
P-8A ---- Wing area 154 m2; span 37.64 m (raked wingtips)
737-900- Wing area 125 m2; span 34.32 m (incl. winglets)