Is that an OEM strap? Having a hard time finding high quality 19mm - definitely one of the downsides to the 321.
Got to be an Omega Flightmaster - such a colourful, vibrant watch (dial, hands, pushers) - impossible to find a vintage 145.026 in excellent cosmetic condition at a reasonable price.
+1 for the Flightmaster. Possibly in titanium to make it lighter? Omega did a great job with the new versions of the Speedmaster Mk II and Ploprof so something similar with the Flightmaster would be cool. Though isn’t it the case that they wouldn’t be able to use the name? So just go with Flitemaster 😉