Since I too will soon be back in the sky and travelling to e.g. the USA, I have fine-tuned and now test run my process for on-the-go lateral flow testing for travel certification.
Should probably add to the wiki now: Flying Yazata COVID-19 Test Centre - CE marked and ISO certified quality.

Antigen (LFT) with travel certificate: approx. 10 €. If I use one of my Roche lateral flow testkits, the price goes up to around 15-16 €, but then it's at least Made in Korea quality. After uploading my results, I received my certificate in less than 10 minutes. Will be interesting to see how my own experience will be, once I'm checking in for my next flight to the USA, but based on FlyerTalk, I should have no issues of concern.
Now, just let it sink in how e.g. Aava charges for something like this still 127/139 €... It's indeed bewildering. There's of course a difference in execution, but the end result is still the same - my nose has been vetted for not having SARS-CoV-2 in my nostrils.
And the certificate as an example that's indeed legitimate and not me talking some crap.

Did some relevant censorship of the details.