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.