There are multiple Imperial War Museums in the UK, and Duxford is likely the biggest plane museum in the country, 7 hangars and next to an active runway used to demonstrations and flights you can rent/pay for. I was there for opening time (took an uber from cambridge as it's not convenient to go by public transport):

first impression: it's big

I had a tour booked to get a private tour of a spitfire and sit in the cockpit. I didn't know that for just 60 times more money, I could have flown in one for 30mn. A bargain :)

this was the actual aircraft, recovered on the beach in normandy

I then went to sit in it

After my tour, I went to visit the hangars:

auto gyro

I went back to hangar #1 to see the concorde that closes earlier:

They had one of the 6 concorde prototypes in the world. I had seen severals, but prototypes are always special, so it was worth seeing:

it never had passengers, it was a test airplane for multiple systems including anti-icing and engine management

the seats in the passenger versions, were much smaller

lots of test equipment

cockpit was off limits

the numbers were references to see how much icing happened

harrier engines are awesome

Next, I went to the restoration hangar, lots of planes being worked on:

Next was a small control room that re-enacted the only real air attack from Germany that was stopped:

Further down was a very nice hangar filled with US planes. Not as interesting to me since I had seem them all many times in the US, but still worth the walk through:

Last, but not least, was land warfare, this was a war museum, not just a plane museum:

And that was it for the visit, I finished just 30mn before closing time.
Also, while I was there, I got to

Those planes did inspire me to do my own flight Over Cambridge From IWM Duxford.

Getting back home was also not easy, no ubers at all, and taxis were a 45mn wait. I got lucky and shared a cab with a woman who had already called a cab herself and was also going to the train station in cambridge.

I was a bit worried about how much time I had as I wanted to see the entire museum, so in the end I settled for a 30mn scenic flight, but there were none, so I rented an old carburated C172 with CFI since I am not legal to fly in the UK and know nothing about radio work, or airspace there.
I hadn't flown a plane like that for about 10 years, but ended up remembering pretty well how to do it. After landing the CFI said he didn't have to touch or correct me on anything and all he did was the radio work.

at least it had a garmin 430, but no autopilot legal to use in the UK

taxing amongst warbirds

good view of the multiple museum hangars

weather/lighting was not great, but a typical UK day. At least, no rain

overflying cambridge airport

weird that they don't use 23L and 23R

We then made it to Cambridge. Forgive the heavy color correction, the original colors were very dull due to the poor weatherpit

Flying over the colleges was very nice.

this delta is where I went punting with Louis, very nice views from the river

We then flew away for a few other views

american cemetery

And back to the airport for an easy landing

the plane still had an ADF antenna

I was going from Liverpool to Cambridge, so I figured I'd stop at Cosford for its enticing RAF museum. I have to say right here that it is not easy to get there by public transport only, unless you have a lot of time. In order to save 1H off the trip, I took a trail to Stafford, got off there and caught a somewhat expensive cab to Cosford (public transport only requires going to Birmingham, and then changing to a once per hour slow train, plus a 10mn walk from the station to the museum).

I got there just before 10:00 as was my plan, and they nicely agreed to stash my luggage which was not a given in the UK (they are more against it as everything is now a bomb apparently). The best part though was that I was able to arrange a private guided tour with a guide called Frank who was a wealth of knowledge on the museum and gave me a 3.5h tour of everything. It was absolutely fantastic, and well worth the 50GBP donation to the otherwise free museum.

The museum is big, 4 different hangars:

this prototype plane actually had an alternate T tail made for it, but it didn't work as the elevator could stall at high angles

the english electric lightening is really a cool powerful plane

when the harrier went to a 98.5 degree angle, it could fly backwards

the brits invented ejection seats and made many different kinds

Frank giving me cool explanations like how this plane had motors to speed up the wheels to landing speed before they touched the ground, how cool is that?

brakes and motor in the same wheel

plane to test alternate pilot positions

this was uncomfortable but allowed the pilot to take more G forces (that was before G suits)

this one is a little bit black bird looking

The section on Japanese aircraft, was surprisingly good:

KI-46-III reconnaissance plane

the Yokosuka Ohka suicide powered rocket, was sobering

Spitfire Mk I

Nice german planes too:

Ju 88R-1 with advanced radar

German U-boats even had this towed autogyro, it didn't have power but would be towed by the submarine and take off high enough to see far away targets

let's not forget the first turbojet powered Me 262, so ahead of its time

and the Me163B-1a komet was liquid fuel rocket powered, super cool too (with dynamo generator in the front for electrical power)

This plane attached to a bomber turned into a bomb that work be flown to and dropped on the target, was interesting too:

A few russian planes too:

More planes in another hangar:

And a good rocket and missile collection too, the germans were way ahead during the end of WWII:

And that was it for the visit. Frank was a fantastic tour guide and really made the visit a lot better. A huge thanks to him and Cosford for putting us in touch.
Getting out timely was not trivial either, but byo sheer luck I was able to call an uber that happened to be driving by and got me 10mn after I called it. Normally it would have been a hard to get cab and a longer trip.