A lot is possible from London, but if you want to play it safe with travel times, stick to RAF Museum Hendon (Colindale tube station), The Science Museum (South Kensington) and the Imperial War Museum (Lambeth North). If you want some other non-aviation but military-themed options, consider HMS Belfast (opposite the Tower of London) and the Cabinet War Rooms (just off Whitehall). All within the London tube network. You can easily do the Brooklands Museum from central London as it is 30 mins away from Waterloo station, just jump on any train that stops at Weybridge, its a 25 min walk from that station. A lot of the other options are further afield and be sure to check opening times. I know I've been burned by that at one point when FAST turned out not to be open on weekdays (or something like that, I cannot remember exactly when I found myself nearby and tried to visit).
If you've got room in your suitcase and the ladies haven't maxed out your credit cards, the Aviation Retail Direct shop at Hillingdon is within the M25, so you could say it's within London.... see:
https://www.aviationretaildirect.com...opening-hours/