I have seen several rankings that call a different casino the best place for Aviator. One seems to give most of its space to bonuses, while another puts the payment section first. I would like to compare them on something more concrete than the star rating. Which checks would you do before even making a shortlist, and what information would help you tell whether a site actually offers the game in the country where you live? It is hard to tell what the rankings are measuring. I am comparing the UK listings.
Use a list such as aviator.uk.net to gather names and then check each one against the same criteria. Start with the operator's legal name, the exact domain and the local regulator's register. For Great Britain, the Gambling Commission's public register lets you search by business name or domain. Once you have confirmed the relevant licence, check the operator's catalogue for the game and see whether it is available where you are. Then compare the withdrawal rules, available spending controls, and the way any offer is explained. Record where you found each detail and the date you checked it. That gives you a shortlist based on requirements you can explain. A star rating can point you towards a page to read, but it cannot establish that those requirements are met.