Used Speedmaster. For me, also a used Navitimer. Seam as well if that is your thing when speaking about “grails”. Tudor is a possibility as well but for me personally, they make great watches but not “grails” so to speak. Highly subjective though.

Speaking of subjective, if you like watches with a bit different style, you can get almost anything from Doxa in that range and have a bit of money over.

I’d keep the Flightmaster. The rest isnt completely my style, although i also somewhat like the Seiko GMT und the Citizen Diver in the top, second frem left.

You could look into aerospace related watches. The Speedmaster has been mentioned before but it’s way out of budget sadly. An alternative with history and similar looks is the Bulova Lunar Pilot. It has a great watch movement and as an engineer by training I enjoy mechanical and good quartz movements equally. It’s super large though and while some watches can get away being rather large, the Lunar Pilot can be too much. Pilots watches could be an other option. They have a lot of history and usually also look pretty clean. And, compared to some other types, you can get very good models at many price ranges. Between Lacos entry models and IWC high end models, there is one for most budgets and almost all are very nice. You can look at Laco for traditional ones (they also made the original ones for the German airforce among other manufacturers), Stowa is another great recommendation more under the radar. Some slightly different models come from Sinn or Guinand as an alternative.

As another, less mentioned option, would be Fortis. The new models are a bit different and imo expensive for what they offer but the older models might be worth a look.

One of the most „Air related“ watch is the Navitimer which is also out of budget but Hamilton has some alternative and the Seiko Flightmaster is also a great option!

The Sinn 144 is also very nice; Sinn in general has a lot of flight related stuff since the founder was an avid pilot. It might be hard to find one for the price since it sadly got pretty expensive lately. The 142 and 157 are also nice. Guinand again offers very similar options (same founder I think).

Breitling Aerospace and Omrga X33 come to mind